Exhaust

[Finkle]

Hey guys i've been lookin into a new exhaust set-up for my truck, right now i have JBA headers and my stock y-pipe has been ripped open by bottoming out too much. I have a single in dual out flow (2.5" or 2 3/4" i believe), iwas looking into tru duals but my main concern is getting a y-pipe that went over the crossmember instead of under. If i was to have a shop make my y-pipe for e what would be a good size to have the y-pipe at and the rest of the exhaust.

Since i have the blower on it i was thinkin that tru duals could actually work, that i mwouldnt lose that much low end but then how would i set up my 02 sensors????

thx for any and all help