Far be it from me to criticise as I don't really bother with designs and that on Forza as a rule, but is that not just the Forza body kit with some wheels in black on with a black bonnet and roof (and presumably boot) and a couple of Ps on the door?
I mean, it looks fine and all that, but it's not really a massive leap over a stock car, is it? Unless, of course, you're just playing with something realistic you'd want to do which in that case fair enough.