I would pay about 10 grand for it (considering the kit and all, GT auto).
If you're looking to race, I'd look for a GTS 6-spd. You could probably grab a used one for 10-15 grand (I would think).
But otherwise, 16 grand seems a bit high to me, I got a new '04 GTS for a bit less than 25 (no body kit or anything though).
I'm sure the other folks here can give you better advice than I can