Yeah thats the one thing about the 930's, they will always hold their value. Id LOVE a 965 but you cant find em anywhere and when you do they run $10k more than a 930 in better condition.
997tt has the PTC centerdiff/transfercase thingy that is obnoxious and will not hold up to time IMHO.
996tt is a proven platform whose only real downfall is its looks. They are tough to work on, but not HALF as bad as a 993tt, whose only real attraction IS its looks.
My 944 Turbo is cheap as fuck but people think its not lol. Pretty easy to work on and parts are still available (for now).