I don't know about the US but over here in Germany, used GT2 are pretty "cheap". Demand seems to have dropped substantially, especially because some people realized that the GT2 isn't the perfect track car as it supposed to be (by it's specs).
If you need a nice track car, save your money and go for the new GT3, modify it to your gusto and be happy.
No doubt, the GT2 is great fun and driving it is spectacular. But it promises more than it delivers, power upgrades are easy but due to the 2WD not recommendable and as a daily driver it might be less enjoyable.