X4M (F98)

Mechanically, almost everything is shared. The F97 X3 M and F98 X4 M use the same S58 engine, gearbox, brakes, suspension and front-end, so downpipes, mid-pipes, intakes, fuelling parts and springs are usually listed for both. The X4 M's coupé roof and rear mean spoilers, rear diffusers, some exhaust tips and rear trim differ. Check the chassis codes on each product, or save your car to My Garage on our site.

Exhaust upgrades lead the way, usually sports-cat downpipes with a matching tune and a cat-back or slip-on system for a stronger S58 sound. Carbon fibre spoilers, diffusers and mirror caps are especially popular on the X4 M because of its coupé styling. Lowering springs, uprated brake pads and paddle shifters complete most builds. Plan software and exhaust together so the calibration matches the hardware.

Yes, for some parts. The 2021 LCI brought revised headlights, rear lights, bumpers and interior screens, and some exhaust and downpipe designs differ between early and late cars. Engine internals, most servicing parts and many chassis upgrades are shared. Check whether a product is listed for pre-LCI, LCI or both, and confirm your car's build date from the VIN if you are unsure which version you have.

Stage 1 software runs on a standard car, but most owners add sports-cat downpipes, an intake and better cooling as power rises. Fuelling becomes the next limit on stock turbos, so auxiliary fuel pumps or port injection appear on higher-output builds, especially with ethanol blends. Uprated spark plugs or coil packs help on tuned cars, and turbo blankets reduce under-bonnet heat during hard driving.

Quality lowering springs designed for the F98 keep the adaptive M suspension and its comfort, sport and sport plus modes. The ride becomes slightly firmer and body roll reduces, while the drop of around 15 to 25 mm closes the wheel arch gap. Large wheels and lower profile tyres affect ride more than springs. Book a four-wheel alignment after fitting to protect tyre wear and handling.

Fitting parts doesn't void the whole warranty, but BMW can refuse claims for faults it believes were caused by modifications, and engine tuning is the most likely to be scrutinised. Every modification, including cosmetic ones, should be declared to your insurer, as undeclared changes can invalidate a policy. Keep receipts and fitting records, and discuss tuning plans with your dealer if your car is still covered.