the 2" piping is from the turbo to the intercooler and 2.25" from the intercooler to the intake manifold. the exhaust has 2.5" and should be fine with my low boost application. stage 3 is very nice but out of my budget right now, remember i can always upgrade when i am ready, but when i do i will upgrade to stage 4 with datalogging and eprom editor. i love the stage 3 and that when you shift gears it keeps it under boost