for much less money, you can up the excitement level of a 996tt, and i would think there are some very good values out there on them. some suspension tweaks, exhaust, chip, short shifter, and you have a substantially different car. it has the right soul, it just has to be uncovered a bit the after market is your friend.

but personally, i don't like AWD or turbo power delivery, so i would go for the GT3, all said and done. the 997 gt3 sounds like it will be closer to the power you are used to in your 993tt (than the 996 gt3).