2g gsx downpipe question

[Roland99gsx]

I tried to search for an answer to this question with no luck. I'm looking to get a 3in downpipe and catback exhaust. On eBay every downpipe I see has a 2.75 inlet but the outlet on the stock o2 housing is 2.5. Should it still mount up to the stock o2 housing? If not can you suggest any cheaper downpipe that do.

 

[dexterholland04]

The overall footprint of the flange should still be the same size. If I'm using a 3" downpipe to a 2.5" O2 housing, then I use a 3" gasket.