I plan on getting a ebay o2 housing. I read its 2.5 inches.

Now I'm wondering which downpipe I should choose. XS Engineering has a 3" dp that clears acd and tie bars. The setback on it is the small donut opening. Looks like its for stock o2 housings.

Or should I get the Tanabe 2.75" downpipe? I'm sure the opening on it is much larger.

 

Look no further than here: www.buschurracing.com

 

it'll fit most of the aftermarket downpipes as the factory 02 outlet is the same size. it's the true 3" 02 housings that need the special downpipes.