KW HAS Kit Explained: Lowering Without Losing Your Adaptive Dampers

KW's own parts approval for the G80 M3 kit allows 15 to 30 mm of drop at the front axle and 10 to 25 mm at the rear. That is 0.6 to 1.2 inches, adjustable at each corner, on the same adaptive dampers the car left the factory with. The window is narrow, and that one fact decides whether a KW HAS kit is right for your car.

This deep dive covers the KW Height Adjustable Spring kit (KW HAS): what is in the box, how far it lowers each car, how it compares with springs and coilovers, the install, and what owners report.

Drop figures come from KW's TUV parts approvals and install sheets, fitment and prices from our own listings, and owner reports from Bimmerpost and Audizine threads.

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The Short Answer

A KW HAS kit is four KW springs on threaded, adjustable perches that bolt onto your factory struts and shocks. Adaptive dampers keep working, so no cancellation module is needed. Drop is modest: 15 to 30 mm front on a G80 M3 or G82 M4, 5 to 20 mm on an F90 M5. Our kits run $884 to $1,854 for BMW and Audi fitments, plus an alignment.

What the KW HAS Kit Is (and What It Is Not)

The KW HAS kit is a height adjustable spring system: KW springs, threaded spring perches, elastomer bump stops and dust boots that fit on the original dampers. KW's description is short and accurate: "Keep your standard dampers." Our listings add that the springs are chrome silicon steel and that KW backs them with a limited lifetime warranty.

Here is the limitation up front. A HAS kit does not change damping, so worn dampers stay worn, and the drop window is smaller than most coilovers. The 8Y RS3 kit is the extreme case: KW measured only 0 to 15 mm front and 0 to 20 mm rear on its test car. If you want the car on the ground, this is the wrong part.

Does the KW HAS Work With Adaptive Dampers and EDC?

Yes, the KW HAS works with factory adaptive dampers, including BMW EDC and Adaptive M suspension and Audi magnetic ride, because those dampers and their wiring stay in the car. None of the owners we read reported fault codes.

That matters for cost. Swap the struts for passive coilovers on a G80 or G82 and you need a KW ESC module ($583.95 on our listing, included in the box with KW's G8x V3 kits) to keep the drive mode buttons working and the dash quiet. With HAS you skip that part, and Comfort, Sport and Sport Plus still change the damping.

Two exceptions are worth knowing before you order. KW's approvals say the kit may not be used on cars with a self levelling system. Some chassis also have separate kits for cars with and without electronic dampers: the 8V S3 and RS3 kit 253100AL is for cars with factory electronic damping, while 253100AK is for cars without it.

How Much Does the KW HAS Lower Each Car?

The KW HAS lowers most BMW M and Audi RS cars between 0.2 and 1.2 inches, and the exact window depends on the chassis. These are KW's measured figures from its TUV parts approvals, taken on KW's test cars, so your result will move a few millimeters with tire size and build tolerances.

The KW HAS kit for the G80 M3, G82 M4 and G87 M2 has the widest window here, and it covers RWD and xDrive cars plus the 2024 M3 CS. The F90 M5 kit and the 8Y RS3 kit are the two smallest windows on the list, so treat them as fender gap tools.

On cars that ship lower from the factory, KW says the drop shrinks by that amount. The G83 M4 Convertible uses a different rear spring (253200EK), so do not order the coupe kit for it.

KW HAS vs Lowering Springs vs Coilovers

KW HAS sits between fixed lowering springs and full coilovers: it costs more than springs, gives you adjustment that springs cannot, and keeps the factory dampers that coilovers throw away. Here is how it lines up on a G80 M3 or G82 M4, using our current prices.

Fixed springs work fine on healthy dampers; our H&R vs Eibach guide covers that choice. The HAS earns its extra cost only if you will use the adjustment, say to raise the car for winter.

When a coilover is still the right call

Buy a coilover when your dampers are worn, when your car has passive dampers anyway, or when you want rebound and compression adjustment for track days. A two way adjustable kit like the KW V3 does that job; KW's DDC line goes further and keeps electronic damping through the drive mode buttons, as on KW's DDC kit for the 8Y RS3, which we carry at $3,994. Our KW V1, V2, V3, Clubsport and DDC buyer's guide walks through each line.

Installation Notes

A KW HAS install is a spring swap: the front struts come out, the factory spring comes off with a compressor, and the KW spring and perch go on the same damper. One G87 M2 owner on Bimmerpost reported 6 hours at an independent shop plus a four wheel alignment, about $1,400 all in.

The front height is set by a measurement, not by eye. KW's G8x sheet calls it measurement A, the distance from the spring seat to the nearest strut fastening screw: 195 to 210 mm on RWD cars and 180 to 195 mm on xDrive cars. It also sets a minimum of 355 mm from wheel center to fender lip at the front of a G80 or G82, and going lower than that is outside the approval.

KW's approval lists three jobs after the install: an alignment, a headlight aim check, and a check of the driver assistance sensors (radar and camera). Set the final height, drive the car a few days so the springs settle, then align. Nothing needs coding.

What Owners Actually Say

Owner reports split between close to stock and firmer than expected, and the complaints cluster around ride on rough roads, front height and noise.

• G80 M3, front would not go low (mixed). A 2024 M3 owner on Bimmerpost set the KW perches at the factory spring mark as he understood the instructions, maxed out the front, and found the front height "basically OE." Other owners pointed him back to KW's measurement A and to checking that the strut was fully seated.
• 8Y RS3, good ride, poor experience (negative). A 2023 RS3 owner on Audizine got about 0.75 in of drop and called the ride "very compliant and not overly stiff or bouncy," but called the kit a pain to adjust and chased noise he traced to the bearings. He returned the kit under KW's warranty.
• G87 M2, mixed but mostly happy. In a second Bimmerpost thread, one KW HAS owner found the front "a little to stiff," another said he loves the setup, and an owner of BMW's own M Performance height adjustable kit called it very close to stock.
• B8 S4 with ADS dampers, long term (positive with a caveat). On Audizine, one owner reported about 70,000 miles on HAS with no issues, while another who installed at 15,000 miles said the ride got harsher after 30,000 miles and would go to coilovers on high mileage dampers.

Sport Plus all the time. A G87 M2 owner on Bimmerpost fitted KW HAS with aftermarket wheels and said the car rocked side to side "with every slight bump," as if the dampers were stuck in Sport Plus, with no error messages. A shop found the install correct. Going back to stock wheels on winter tires made it "significantly better," and another owner running the kit fully lowered said he was fine with the compromise.

Mistakes We See

• Setting the front by the old spring mark. Use KW's measurement A for your chassis and drivetrain. The G80 thread above is what happens otherwise.
• Ordering the coupe kit for a convertible. The G83 M4 Convertible, E93 M3 and some other drop tops use different rear springs. Match the body style as well as the model.
• Ignoring the damper type. On cars sold with and without electronic dampers, such as the 8V S3 and RS3, KW makes separate kits. Check your build sheet.
• Putting new springs on tired dampers. The S4 owner who installed at 15,000 miles found the ride harsher past 30,000. On a high mileage car, budget for dampers or go straight to a coilover.
• Expecting a slammed look. A 30 mm maximum front drop closes the gap. It does not tuck the tire.

Who This Is For (and Who Should Skip It)

Buy a KW HAS if you own an M car, RS model or AMG with adaptive dampers in good health, you want to close the fender gap, and you value being able to adjust height later.

Skip it if your car has passive dampers, if your dampers are high mileage, or if you want a big drop. Skip it too if you only want one fixed height and never plan to touch it: a set of H&R or Eibach springs at $395 to $509 on a G8x does that for well under half the money. Our coilovers vs lowering springs guide has the wider comparison.

If It Were Our Car

• G80 M3 or G82 M4: KW HAS 253200EB, front about 25 mm down and rear about 20 mm down, Comfort mode for the commute.
• G87 M2: KW HAS, but keep stock wheel and tire sizes until you have driven it, given the rocking reports.
• F90 M5 or M8: HAS only if 5 to 20 mm is the look you want. It is a subtle change on a heavy car.
• 8Y RS3: We would think twice. A drop of at most 15 mm front for $884 is thin value; fixed springs or the DDC coilover make more sense depending on budget.
• 8V RS3 with magnetic ride: HAS 253100AL if the dampers are healthy, coilovers with a cancellation kit if they are not.

Buying a KW HAS From Us

We are an authorized dealer for every brand we carry, KW included, and in stock hardware ships fast. Each of our HAS listings names the KW part number and links KW's install sheets, so you can check measurement A before you order. If you are unsure which kit fits your body style or damper option, email us your VIN and we will match it. Return terms are on our refund policy page.

Find Your KW HAS Kit

The Bottom Line

The KW HAS kit is the cleanest way to lower a car with good adaptive dampers and keep every drive mode working. Its drop window is honest but narrow, 15 to 30 mm at best on a G8x and less on an M5 or 8Y RS3. On a G8x it costs about $785 to $899 more than fixed springs, so the adjustment has to be worth something to you. If your dampers are tired or you want real height, buy a coilover instead.

Frequently Asked Questions

What is a KW HAS kit?

It is KW's Height Adjustable Spring kit: KW springs on threaded perches, plus bump stops and dust boots, that install on your factory dampers. You adjust ride height at each corner like a coilover, but the original struts and shocks stay in the car.

Does KW HAS work with BMW EDC and Audi magnetic ride?

Yes. The factory adaptive dampers stay in place, so drive modes keep working and no cancellation module is needed. On some chassis, such as the 8V S3 and RS3, KW sells separate kits for cars with and without electronic dampers.

How much does the KW HAS lower a G80 M3?

KW's parts approval lists 15 to 30 mm at the front and 10 to 25 mm at the rear for the G80 M3 and G82 M4, about 0.6 to 1.2 inches front. The G87 M2 gets 15 to 30 mm front and 5 to 20 mm rear with the same kit.

Do I need an alignment after installing KW HAS?

Yes. KW's approval requires an alignment, a headlight aim check and a check of the radar and camera sensors after lowering. Let the springs settle for a few days first.

Is KW HAS better than lowering springs?

It is better only if you want adjustable height. Fixed springs from H&R or Eibach also keep adaptive dampers working and cost $395 to $509 on a G8x versus $1,294 for the HAS kit.

Will KW HAS make my ride harsher?

Owner reports are mixed. Some G87 M2 and S4 owners describe it as close to stock, while others found the front stiffer or the car rocking on rough roads, especially with larger aftermarket wheels or high mileage dampers.