T3/T4 dosen't mean a whole lot, what does the turbo map look like and where do you want it to "hit" in the power band? How much boost do you plan to run and what is your end game effective compression ratio? Do you plan on modifying the engine to handle more than 12:1? You WILL have to run 91 or better octane fuel. Go here http://www.turbobygarrett.com/
and under "Turbo Tech" start with turbo 101. You may be in for more than you're bargaining for, maybe not. But get the info from the guys who develop and make the stuff, and good luck.