BMW F20 F30 F80 Bilstein B3 Rear Coil Spring 36-251254

Bilstein B3 rear coil spring 36-251254 - not a generic 'OE replacement', but the exact spring used by fast-road and track-day drivers on F20, F30 and F80 chassis with N13, N20, N55 or S55 engines.

• Fits: F20 120d xDrive, 125d | F30 316i, 320i, 328i, 335i | F80 M3 (non-M DCT models only)
• Drop-in for stage 1 or stage 2 builds where you want predictable rear geometry without lowering more than 10mm
• No decat or exhaust mods needed - this is suspension-only; works with stock or fast-road exhausts
• Hot-set, surface-compressed chrome vanadium steel - zero height loss, no sag, no guesswork
• Not for G20/G22 - those need different rates and free lengths

Search terms this actually matches: BMW F20 rear coil spring, F30 N55 rear spring, F80 non-M3 rear coil, Bilstein B3 36-251254, stage 2 BMW rear spring, fast-road rear suspension upgrade.