Despite its current range-topping status, the G20 M340i xDrive failed to impress when we got behind the wheel. One thing it most certainly does have, however, is straight-line performance, but as is the way of the tuning world, G-Power felt it wasn’t enough.
Three levels of power are on offer, starting with the GP-420 kit and moving up to the GP-510. The baseline tune is good for an F80 M3-rivalling 308kW and 600Nm – the 0-100km/h sprint drops four-tenths over factory to only 4.0sec, with top speed coming in at 300km/h should you opt for the limiter removal.
GP-470 requires a little more than an ECU tune, with a new stainless steel downpipe and less restrictive 200-cell catalytic converter allowing for reduced backpressure. The result is 346kW and 650Nm of torque, helping the 3-series sprint from standstill to 100km/h in 3.8sec.
Pushing the B58 straight-six to the max is G-Power’s GP-510 kit, adding a new turbocharger with enlarged compressor and turbine wheels and larger CNC-milled housings for higher peak boost. Combined with its sports downpipe, 200-cell catalytic converter and an ECU tune, output comes to a G20 M3-matching 375kW and 690Nm, providing a 3.7sec 0-100km/h time.
All three stages offer improved throttle response, torque delivery and, supposedly, fuel economy (though that will be entirely dependent on a well-trained right foot…). A valved exhaust system with larger exits, the 300km/h top speed increase, aluminium intake pipes, lightweight 20-inch forged wheels and much more are available across all three variants.