I don't know the answer for you, but I don't see any bad options of the ones you listed! There is too much instability in the "Street" autocross classes for me to buy a car specifically for one of those classes again because I keep cars for a long time.
The power and wheel size should make it quite good. I didn't re-read the link, but what is the weight? I'd think the biggest issue is that (I assume) you'd have a pretty big payment or amount to shell out for a pretty similar car to what you have now.
You could get a V8 truck and put an exhaust on it?
