Cobalt turbo or SC?
Didnt know in 2003 there was a 5.0 mustang, i thought "SS" was GM. If your talking about a cobra... thats the year they were SC and he will beat you.
The R32 is N/A so the exhaust and chip wont increase power over stock that much. close race i think.
g35x while quick when RWD, the AWD really eats up its mid and top end speed and its a bit heavy.