Since you mentioned a GT500.....why not consider a 13/14? As for the GT350 with/without R, it's a sweet ride, especially at their sweet spot in the higher RPMs. If you want to have some track day fun, that would be a good right out of the box way to go. If you're looking for the odd high speed sprint....I'd go with the GT500. While the late model Blackstock modded GT's are sweet....they don't seem to retain their value like GT350/GT500's do. Something to consider....

PS> If you get a GT350/R.....I'd recommend you make sure you have an extended warranty, just in case you pick up one of the heavy oil eaters and need a new motor.