You've got to think of the size of the turbos. These little things aren't punching out enough air to need more than 2.5
I run 3" x2 on my G35 set up, and it's overkill. But the turbos are pretty moderate, and I wanted to be spoolin before 3k
This platform will never have that issue no matter what turbo's someone squeezes in here
PLUS-- there's always cutouts mate.