Okay so first off, the piping connecting to the in/out of the resonator are 2.25" on 97-03 Grand Prix GTs right? Then smaller after the Y? My question is, I want 2.5" all the way from the cat back to the mufflers but don't want to remove the resonator. Would a muffler shop be able to make that work or would they have to do all 2.25"?