I have been thinking about putting 2 in 1 pipe on my Ultra. Right now its a stock 88, I will be adding a Power Comander to handle the new pipes. My local indy, "Ricks Cycle Parts" has a set that were bought for a big bore motor, (103) they will fit my scoot. Now my question. will these pipes work on my scoot knowing that some backpressure is required to operate correctly. or will they be too large and not have the correct pressure? I was looking at a Thunder Header, but its a little out of my price range. I can get this other header for a lot less than the thunder header. could I just measure the inside diameter to check?. other than just installing and trying them out, is there another way to check? thanks Trickydoc.