ST Coilovers vs KW: Same Company, So What Are You Paying For?

$1,205. That is the gap between the ST XA and the KW V2 for a rear wheel drive F30 335i on our shelf, and both kits have the same 16 click rebound adjuster, the same threaded height adjustment, and the same hand built, dyno tested twin tube damper from the same factory in Fichtenberg, Germany. ST Suspensions is a KW brand, so the question is not whether ST is a KW knockoff. It is what the extra money buys.

This ST vs KW comparison walks the ladder from the ST X, the cheapest German built coilover we sell, up through the ST XA and XTA to the KW V1, V2 and V3, and tells you where the two brands are the same part in different clothes, where KW gives you something ST does not, and which rung belongs on your car.

Construction, click counts and warranty terms come from ST's and KW's own product pages, installation instructions and North American warranty policies. Owner reports come from M3Post, 1Addicts, Audizine, SpoolStreet and a Mustang owners forum. Prices are ours, in US dollars, and vary by car.

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The Short Answer

Buy the ST XA ($1,419 on most BMWs) if you want KW damping with rebound adjustment on a street car and live where the roads are not salted all winter. Buy the KW V2 ($2,624 on a rear wheel drive F30) if you want the same adjuster in a stainless body with a lifetime warranty. Buy the ST XTA ($1,859 on an F80 M3) if camber plates matter more to you than a compression knob, and the KW V3 ($3,594 on the same car) if the compression knob matters more. Nobody needs both brands on the same car.

Who Actually Makes ST Coilovers

ST Suspensions started in Southern California in 1979 as Suspension Techniques, a sway bar and lowering spring company. Belltech bought it in the 1990s, and in 2005 KW automotive bought both Belltech and ST and used them to form KW automotive North America. ST's sway bars, research and tech support still live in Clovis, California, but every ST coilover kit is built by hand at KW's plant in Fichtenberg, Germany, on the same twin tube damper design KW uses for its V1, V2 and V3, and every damper is run on a KW shock dyno before it goes in the box.

That is why ST describes its coilovers as "developed alongside KW" and why the ST X was openly modeled on a galvanized version of the KW V1. The two brands are not competitors that happen to share an owner. ST is KW's value line, priced and finished for drivers who want the engineering without the stainless steel and the lifetime warranty.

The Ladder, Rung by Rung

Each ST line has a KW twin, and the differences between the pairs are the body material, the warranty and the price. The two places the ladders diverge are the top mounts and the compression adjuster.

Our KW buyers guide covers the KW side of this table in more depth, including the Clubsport, DDC and HAS kits that have no ST equivalent.

ST X vs KW V1: the same damper, two different bodies

The ST X is a height adjustable coilover with damping KW sets for each car and locks. So is the KW V1. Both use a threaded strut body, a polyamide composite spring perch with a stainless steel insert so the collar keeps turning years later, a chrome plated piston rod, and KW's multi layer seal and dust protection package. The ST body is zinc coated steel with an additional coating on top; the KW body is stainless, which KW calls inox line.

The ST X for the E90 3 Series is $1,089. KW's V1 for a comparable non M BMW runs about $2,094, which is the F30 and F32 xDrive kit. On that xDrive F30 the ST XA is $1,419, so you can buy the adjustable ST for $675 less than the non adjustable KW.

ST XA vs KW V2: 16 clicks each

The ST XA adds a 16 click rebound adjuster at the top of the piston rod, turned without tools or disassembly. The KW V2 adds a 16 click rebound adjuster at the top of the piston rod. KW calls its version TVR-A valving; ST calls its version KW damping technology, which is the same thing described from the other side of the catalog. Both ship preset to the factory recommended setting with a setup card so you can get back to the baseline.

For a rear wheel drive 335i, 340i, 435i, 440i, M235i or M240i without EDC, the ST XA is $1,419 and the KW V2 is $2,624. ST publishes a lowering range of roughly 1.2 to 2.4 inches at the front on that kit; KW's V2 range for the same cars is similar, and both carry a parts approval certificate.

ST XTA vs KW V3: camber plates or a compression knob

This is the rung where the two brands stop mirroring each other. The ST XTA keeps the XA's 16 click rebound adjuster and adds aluminum uniball top mounts with scaled camber adjustment at the front, plus a linear race spring set. The KW V3 keeps the V2's 16 click rebound adjuster and adds a separate 12 click low speed compression adjuster at the base of the strut, but reuses your factory top mounts, so no camber plates. To get camber plates from KW you step to the Clubsport, which carries a 90 day warranty.

On an F80 M3 or F82 M4 the ST XTA is $1,859 and the KW V3 without EDC is $3,594, or $3,894 as the bundle with EDC cancellation. So the $1,735 question on an M3 is which adjustment you will actually use. An owner who runs track days on street tires will reach for camber first. An owner who drives fast on the road and wants to tune nose dive under braking will reach for compression.

ST XTA Plus 3: more clicks than a V3 for less money

The XTA Plus 3 is ST's three way kit: 18 clicks of rebound, 24 clicks of low speed compression and 24 clicks of high speed compression, with the XTA's uniball camber plates and race springs. KW's own three way street kit is the V4, which we list only for the heaviest M cars, so on an E46 M3 the XTA Plus 3 at $2,909 is cheaper than the two way KW V3 at $3,094. The trade is the same as everywhere else on the ladder: a galvanized body and a five year warranty instead of stainless and lifetime.

What the Extra Money Buys

Across every pair, KW charges roughly $700 to $1,700 more than ST for the same damping. That money buys four things, and only two of them matter to most owners.

• Stainless steel struts. KW's inox line bodies do not rust, full stop. ST's are zinc coated steel with a second coating over the zinc, which ST says is sealed multiple times for all weather use. In Arizona, Texas or California the difference is cosmetic. In the salt belt, a ten year old ST body will show its age where a KW body will not, and a seized spring collar is the usual complaint on cheap coilovers, which is why both brands put a composite perch on a stainless insert so the threads keep turning either way.
• A lifetime warranty instead of five years. KW North America covers V1, V2, V3, V4, DDC and HAS for the life of the original purchaser's ownership, with no mileage limit. ST covers its coilovers for five years, unlimited mileage, to the original purchaser. Five years is longer than most people keep a modified car, and a SpoolStreet owner who filed a lifetime claim on 13 year old KW V1s reported that KW honored it but required the struts to come off the car, be shipped disassembled and wait about two months for inspection. The lifetime warranty is real; it is not free in time.
• A compression adjuster, on the V3 only. No ST kit below the XTA Plus 3 lets you touch compression. If you want to firm up the nose under braking without changing springs, the V3 is the only two way option on either ladder.
• The badge. KW is the name more buyers search for on the used market, which matters if you sell the car with the suspension on it.

What the extra money does not buy: a different damper. The piston, the valving principle, the dyno test, the serial number and the hands that assemble it are the same.

Same Car, Two Prices

These are our current prices on the pairs customers ask about most. The ST kit is the first number in each row.

EDC Cars: Read the Listing Twice

Both brands split their BMW kits by drivetrain and by whether the car has Electronic Damper Control. ST sells the F2x and F3x XA as a kit for cars without EDC and a separate kit for cars with EDC, both $1,419; KW does the same with its V1, V2 and V3. If your car has adaptive dampers, a passive coilover from either brand needs an EDC cancellation module to keep the dash quiet and the drive modes working. KW's cancellation kit for the F30 and F32 is $503.95 and works under an ST kit too. The quick test: if a button on the console changes the suspension, you have EDC.

What Owners Actually Say

The ST reports below are the most detailed first hand ones we could find on BMW forums. Most are on the XTA, because that is the ST kit M car owners buy.

The 30,000 mile report. An E9x M3 owner on M3Post who replaced blown EDC dampers with ST XTAs at about 80,000 miles reported 30,000 miles on them, including a rock strike hard enough to crack the subframe and a wheel. The strut came out fine. He bought the kit for the camber plates, which he said reach a bit more than three degrees, and runs full stiff at the front with the rear three quarters up because the rear bounces with rebound maxed. Fully soft, he called the car more comfortable than stock.

• E9x M3, ST XTA, two track days at Laguna Seca (M3Post). The owner found the car a little floaty in the heaviest braking zones and the fast sweepers, but said the suspension performed great, and the only change he would consider for a dedicated track car was higher spring rates. Mixed, in the same way F80 owners describe the KW V3 on track.
• E36 M3 and E90, ST XTA (M3Post). One owner said his wife does not complain about the ride, that passengers have gone on to buy ST after a drive, and that he would buy a second XTA set for his E90. Positive.
• E82 135i, ST XTA, daily with track days (1Addicts). Comfortable on the street, fast on back roads and good on track once he found his settings. Positive.
• Mustang and FR-S, ST XTA, 20,000 miles (S197 forum). A suspension shop owner who runs XTAs on several cars hit a pothole in New Mexico that destroyed a tire and two wheels; the dampers were fine. He summarized the V3 versus XTA choice as double adjustable and stainless against single adjustable, plated steel and included camber plates. Positive.
• B8 Audi, ST vs KW V1 (Audizine). A thread arguing whether stainless was worth the price gap concluded that the only other difference was the warranty, and one poster said the gap should be a couple of hundred dollars if that were true. That argument is the whole reason this article exists.

The consistent thread across those reports: nobody complains about ST damping quality. The complaints that do exist, a bouncy rear at full stiff and float on a race track, are the same ones F80 owners raise about the KW V3 in our KW guide, which is what you would expect from the same damper.

Mistakes We See

• Paying for stainless in the desert. If the car has never seen road salt, the ST body will look the same as the KW body for as long as you own it. Spend the gap on an alignment and tires.
• Buying the V3 for camber. The V3 reuses your factory top mounts. If camber plates are the goal, the XTA has them and costs half as much, and the KW answer is the Clubsport, not the V3.
• Buying the XTA for compression. The XTA has no compression adjuster. If you want to tune dive and squat separately from rebound, you need the V3 or the XTA Plus 3.
• Ordering the non EDC kit for an EDC car. Both brands split the kits. A passive coilover on an adaptive damper car without a cancellation module means a fault on the dash and dead drive modes.
• Skipping the alignment and sensor checks. Both brands' approvals call for a four wheel alignment after install, plus a headlight aim check and a check of the radar and camera sensors on cars with driver assistance.

Who This Is For (and Who Should Skip It)

ST is for the owner who wants a German built, KW engineered coilover on a street car and would rather spend the difference elsewhere, especially in a dry climate or on a car that will be sold within five years. KW is for the owner who keeps cars a long time in a salt state, who sells cars with the suspension on them, or who wants a compression adjuster without stepping up to a three way kit.

Skip both if your dampers are healthy and an inch lower is the whole goal; our coilovers vs lowering springs guide explains why springs cost a fraction. And skip the XTA or V3 if you run three or more track days a year on an M car; owners of both kits on M3Post and Bimmerpost end up wanting stiffer springs or a dedicated track damper, and our KW V3 vs Ohlins comparison covers that next step.

If It Were Our Car

F30 335i or 340i daily, rear wheel drive, sunbelt: the ST XA at $1,419. Same 16 clicks as the V2, $1,205 left for tires and an alignment.

Same car in New York, Chicago or Boston, kept ten years: the KW V2 at $2,624. The stainless body earns its keep by the fourth winter.

F30 or G20 xDrive: the ST XA at $1,419. It is cheaper than the KW V1 on the same car and adjustable, and the V2 is a $1,295 step for the same adjuster.

F80 M3 or F82 M4, street with a couple of track days: the ST XTA at $1,859 for the camber plates. Set front camber for the track days, soften rebound for the drive home.

F80 M3, fast road driving, no track: the KW V3 at $3,594, set once and left alone, because the compression adjuster is what you will use.

E46 M3 being built for track days: the ST XTA Plus 3 at $2,909. Three way adjustment and camber plates for less than a two way V3.

Buying, Warranty and Returns

We are an authorized dealer for every brand we carry, ST Suspensions and KW included, so every kit is factory sealed and the maker's warranty applies: five years on ST, limited lifetime on KW's V line. In stock hardware ships fast, and our price match covers other authorized dealers. Coilovers are final sale unless defective under our Returns and Refunds policy, so match the chassis, the drivetrain and the EDC version before you order. Not sure which kit your car takes? Email us your VIN and we will confirm fitment in writing before you buy.

Shop KW Coilovers

The Bottom Line

ST and KW coilovers are the same damper, built by the same people, in two bodies at two prices. The ST X and XA are the KW V1 and V2 in zinc coated steel with a five year warranty, for $700 to $1,300 less on the same BMW. The XTA gives you camber plates the V3 does not; the V3 gives you a compression adjuster the XTA does not. Pick by climate, how long you will keep the car, and which knob you will actually turn, not by the badge.

Frequently Asked Questions

Is ST Suspensions owned by KW?

Yes. KW automotive bought ST Suspensions and Belltech in 2005 and formed KW automotive North America. ST coilovers are built by hand at KW's factory in Fichtenberg, Germany, and dyno tested there before shipping.

What is the difference between ST XA and KW V2 coilovers?

Both are height adjustable twin tube coilovers with a 16 click rebound adjuster. The ST XA uses galvanized zinc coated steel struts and carries a five year warranty; the KW V2 uses stainless steel struts and carries KW's limited lifetime warranty. On a rear wheel drive F30 the ST XA is $1,419 and the KW V2 is $2,624.

Is the ST X the same as the KW V1?

The ST X is modeled on the KW V1: same twin tube damper design, factory preset damping, threaded height adjustment and composite spring perch. The difference is the galvanized steel body instead of stainless and a five year warranty instead of lifetime. The ST X is $1,089 on the E90 3 Series.

Does the ST XTA have compression adjustment?

No. The ST XTA adjusts rebound only, in 16 clicks, and adds aluminum uniball camber adjustable top mounts. For compression adjustment you need the KW V3, with 12 clicks of low speed compression, or the ST XTA Plus 3, with 24 clicks each of low and high speed compression.

What warranty do ST coilovers have?

ST Suspensions covers its coilovers in North America for five years with unlimited mileage, to the original purchaser. KW covers its V1, V2, V3, V4, DDC and HAS lines with a limited lifetime warranty, and its Clubsport kits for 90 days.

Will ST coilovers rust?

ST struts are galvanized zinc coated steel with an additional coating and a multi layer seal package, built for all weather use. They resist corrosion well, but they are not stainless like KW's inox line bodies, so in heavy road salt a KW body will look better after many winters. Both brands use a composite spring perch with a stainless insert so the height collar keeps turning.