ITs about rpm + capacity + boost mate, its not just T34=5500rpm, it is in a cossie at 25psi, but it wont be on a 7 litre v8 at 10 psi, that why you need to give more details before anyoen can be useful.

Two huge turbos like GT42's seems very over the top, as its going to be laggier than two GT30R's which would do the job just as well at that level.

But ONLY if they are on their compressor map at the boost you want, and you still havent said what that is so no one can help!

More details needed, a lot more details!


What CR is it?
What boost are you going to need?
What volume is it?