[Obioban]

I would expect the benefits to break down as follows, given equal tires but otherwise stock:
Acceleration: M2
stopping distance: tie
fade resistance: M2
torque: M2
throttle response: M3
steering feel: M3
short term reliability: M2 (warranty/new car FTW)
long term reliability: M3 (turbos FTL)
Interior quality vs a nice e46: M3
interior quality vs a typical e46: M2
back seat space: M3
differential's ability to put power down: M2
superior powerband: depends on owner's taste
gauges: M3
ease of servicing/modding: M3
interior engine sound: M3
exterior exhaust note: M2
properly centered driver's seat: M3
stock vs stock lap times with professional driver: M2
real world tracked car lap times: driver/mod based
gadgets/gizmos/driver assists: M2
looks: M3 (subjective, technically... but I don't think anyone's going to disagree)