As above, speak to Mark but if you are on a T34 with a 63 then the 7064 will not be overkill...you don't have to wind the boost up and it will spool much faster than what you have now, it will be night and day. I went t34 to 7064 but I didn't have the big 63 on mine and it still spools up faster. Mine made 468bhp on a std engine but you don't need to have so much boost if you don't want it. I think the smaller one is now twin scroll but it is the twin scroll and the manifold to run it where the magic happens....if you can get both with the smaller one then I bet that will be impressive.