I looked at the same thing. I came up with this...It would take alot of money to even get a n/a to get the hp of a TT. And even to re-build your n/a engine would be just as pricy as swapping to a TT. Mods with a TT engine gain so much more hp than a n/a. I finally broke down and decided to either sell my n/a for a TT or just do the swap. If you want the most power you can get out of your Z TT is the way to go!!!