Is this legal? The only possible problem I saw was the intake restrictor plate diameter.

 

Yes its FP legal. I Run FP. Yes its Fun. Eventually I might even learn to drive well enough to overcome the FP PAX.

No one cares about the restrictor plate until you start winning. 2" restrictor-- its not much of a change on the r53. I don't know about the r56.

See My thread in Street Mod (there's no prepared forum)

SMF is probably easier to build to since you can use real Aero (8sqft wing) to get downforce on the rear end.

FP only allows stock aero (bling not wing). a 1900lb FP mini weigh less than 400 lbs per rear corner fully wet. aero at the back of the mini is all draft. deleteing the mufflers creates a void that is followed by the rear skirt creating lift. the rear end needs to take most of the roll and weight transfer. without aero downforce it is very tempermental. I have dreams about downforce. When I can get the car down to1500 lbs I'll run XP just to get downforce.
also the calculated weight for a MCS in FP is about 1650 Lbs. the minimum weight for the class is 1900 which is the calculated be the weight of a 1.8T FWD. So a little bit of a handicap there.

Let me know if you come to FP. There's a lot of z cars that need taking down.