So i'm trying to help this guy get going in ITS, he just had his first race weekend and was disappointed in his lap times. I'm not surprised, as he's got a freakin street car with a roll cage in it (even rolled across the scales around 2900lbs).

he's got some sort of aftermarket shocks, a cone filter, header and exhaust of unknown origin.

i've been trying to read up on these things, but i have next to no experience with the P-Cars. he wants to build the car to be legal to run in both SCCA ITS and NASA Spec 944. if you were to prioritize your build with keeping a limited budget in mind, what would you change that would have the most dramatic effect on laptime/$.

PS - ITS isn't very competitive in this division, so pro-motors need not apply.