03-04 Cobras are a blast and can be bought easily in your range. I've never owned a GTO but I've spent some time in a friend's and I love the interior in them. Any car I'll be spending a lot of time in, the interior is a deal breaker.
I'm not saying I'd suggest it over some other choices posted, but a Genesis coupe hasn't been mentioned that I saw. New enough for warranty, rwd, either engine option has potential to be fun but no monster, they look great IMO, and fit within your budget.