Which is fasted and the most tunable, under 10000.?

I like how he supported his thoughtless, factless answer with an openly thoughtless factless answer. The RX8 is a tourqueless wonder, and is slow especially in automatic form. It compensates by having a wonderful RWD chassis, a good interior and interesting styling. The 260hp turbo Cobalts are great, but for 10k you're probably looking at a 205hp supercharged model which are somewhat less so. Neither of theses cars are all that fast or have huge aftermarket support frankly. Youd be better off with a Fbody or Mustang