G30 | G31 | G38 (2017+)

The 540i has the widest choice of performance parts, because its B58 straight-six is shared with many tuned BMWs and responds well to software, a sports-cat downpipe and exhaust. The M550i has more power from the factory but its V8 runs hotter and is more complex to modify. The 520d and 530e are better suited to chassis, brake, interior and styling upgrades than to chasing power.

On earlier 540i models with the first-generation B58, the plastic charge pipe is a well-known weak point and can split once boost is raised, so many owners replace it with a stronger aftermarket pipe before or alongside a tune. Check which B58 version your car has, as later engines use revised parts. Fit any replacement with good clamps and seals to avoid boost leaks.

Yes. A sports-cat downpipe, such as the Deep Tone Industries designs for the B58, changes exhaust flow and boost behaviour, so it should be paired with software written for it. Without a matching map you can expect fault codes and inconsistent boost. The car must still meet UK MOT emissions and noise limits, so a quality catalysed downpipe is essential.

The B47 2.0-litre diesel is generally reliable when properly serviced, and a remap typically brings a useful lift in mid-range torque for overtaking and towing. The ZF eight-speed gearbox copes well with sensible increases. Keep service intervals short, use quality oil and choose a reputable tuner. Many 520d owners also upgrade brakes and handling, which improves the car without affecting the engine.

Engine, brake and most interior parts are shared, but rear suspension differs, with many Tourings using self-levelling rear air springs, so springs and coilovers are often body-specific. Exhaust systems and rear styling parts also differ, and the G38 long-wheelbase car has its own body parts. R44 lists exact G30, G31 and G38 fitment on every product, and My Garage filters the range for your car.

Yes, the twin-turbo N63 V8 responds strongly to software, but it generates a lot of heat and benefits from careful maintenance, including regular oil changes and attention to cooling. Cars built from around mid-2020, which includes most facelifted 530PS models, have a locked engine computer that needs a specialist bench unlock before tuning. Uprated brake pads and fluid are a sensible companion to any added power.