wanting something cheaper but faster

280z/300zx

Other things to consider. Are you paying cash out right for your next car or looking to finance? If you looking to finance you can't really go too old on a car otherwise you will have trouble with a bank cutting you a loan. Not to mention used cars tend to have high interest rates. I mean cars to consider would be a used C6 Vette. You can find 08's and 09's for around 30k, sometimes less. You can even find 05-06's in the mid 20's, but again financing a car this old will be more difficult. Not to mention you are talking about a car that may or may not have been taken car of.

I think a cheaper car that is faster and yet still easy to find and finance would be a mustang GT. There are 2011's that are now slightly used hitting the dealers, financing a 2011 won't be that hard to do, and it's a faster car for sure.

Now if your paying cash out right for a car then you have far more options

PS. Yes, you paid too much for your car which is why you still owe so much on it. This will make it difficult to get out from under it