Ok, lets not get crazy here. First of all, you can actually BUY the Imp, try getting an awd focus or pug, THEY DON"T EXIST!! What this means is that WRC class C (or N or whatever it is) cars aren't particularly close to their road going brethren, aside from engine location, and more importantly in this case, wheel location. The stock new one is heavier, my guess is it will be at the weight requirement in racing trim, but has wider tracks front and rear, this will help in the handling dept.
The pug and focus have no overhangs which can help the car rotate in turns, more centralized mass, and that advantage doesn't go away entirely, although I think they pushed the wheels out to the corners a bit, on the new Imp.
Bottom line is, racing is great and all, but my bucks go to the company that brings that to the street.
GO TEAM SUBARU!!!