Dinan Performance Lowering Spring Set - BMW X3 M40i / X4 M40i (G01/G02) 2018-2025

Dinan's Performance Spring Set replaces the factory coils on the X3 M40i and X4 M40i with two front linear rate springs and two rear dual rate springs, tuned for a 25% increase in stiffness front and rear. The set lowers the vehicle 7/8 inch (22mm) at both ends for tighter suspension geometry and a more aggressive stance. Each spring is CNC wound from high tensile chrome silicon wire and shot-peened for stress relief, then preset to prevent sag, reducing body roll and dive while sharpening steering response. The Ride Quality and Handling Kit is sold separately.

Specifications

Documents: Installation Instructions (PDF)

This part fits:

Shipping

• In-stock orders placed before 3 PM EST ship the same day — everything else ships within 24 hours.
• Standard, expedited, and overnight options at checkout.
• Oversized items ship by freight and take longer.
• Backordered items ship as soon as stock lands — contact us for lead times.
• International orders: prices do not include VAT, duties, or import fees. Your country charges these at import and they are the buyer’s responsibility.

Returns

• 30-day returns on new, uninstalled items in original packaging with all hardware.
• Standard returns: 8% restocking fee, buyer pays return shipping. Both waived if the item is defective or we made the error.
• Installed or used parts can’t be returned — confirm fitment before you install.
• Special orders and custom items are final sale.
• Email us for return authorization before shipping anything back.

Full details: Shipping Policy · Refund Policy