Excuse my lack of knowledge about Garretts, but what size turbo is it? I'm about to be running a single S475.
I have done a fair amount myself. I'd like to run water/AIT but I know at this point it's not practical.bi don't really want to spend 800-1200 on a replacement unless what I'm getting is really worth my time. Why run larger piping? Plenty of guys making tons of power on 3-3.5" piping.
76mm dbl ball bearing charger. Its a gt4202r with a JEB 6 blade wheel.
The larger piping will yield less restriction, and carry more volume.