Re: 2006 stang or '11
06 GT - with matching mods will outperform the 11 V6, more torque, V8 sound, more HP/TQ potential.
11 V6 - newer car, good 0-60 can be modded up. But no V8 sound or torque.
Kinda depends on what you want out of the car. If it's DD and not looking for dumping a lot of $ in to it, then V6 maybe ok. But if you want that mean sound, modded up some extra performance, then the Gt will be better.