You just simply have no need for anything more than a T3 if you run std boost - if your wanting to up the power then a T38 is a good option - i've had both T34 .48 and currently sitting in the car is a T38 .63 - personally i don't like T34's mine was gutless, some people say it's the perfect road spec but i dissagree my T38 is proven to start making +boost around 2500rpm and peaks 35psi