C4 Corvette, probably the least appreciated generation of Corvette aside from the 1953 model with the Blue Fire inline 6.
i said 535i before. Now if you want a muscle car with a decent amount of tuning options either the Caprice/roadmaster from the 1990's or the ford crown victoria
Cheapest 2015 Mustang GT I can find is about 25k, at least somewhat near where I live, might be different in other parts of the US. I have found a few 2004 - 2006 Mustangs that are around 7 - 8k though.