Anyone here have the Greddy kit on their 99-00 Si with a upgraded downpipe? Im looking to upgrade the downpipe from its 1 7/8 inch to a 2.5 inch but i've heard by getting a bigger downpipe, it makes it harder to hold boost under 10-12 psi.

 

I think a lot of people end up having to port out the w/g hole.