I agree,
Engine M3 Convertible
Cylinders: 6
Valves: 24
Capacity: 3246 cc
Maximum Power: 252 kW / 343 bhp / 7900 rpm
Maximum Torque: 365 Nm / 4900 rpm
Acceleration 0-100km/h: 5.5 s
As you can see, not much HP between Uber's and the Factory, besides the N20... So the only thing i could think of is the speaker system brings the weight up, put the extra Hp and N20 brings it back down to the factory runs.
Well who cares Quote: Supercharger/Turbocharger: Coming soon