All i know is that with the RSX, when u add an after market header u need to replace the o2 sensor with an o2 simulator, otherwise you'll throw a check engine light (CEL)
a popular and well recomended o2 simulator is the Caspers Electronics o2 simulator
http://www.casperselectronics.com/cgi-local/store/commerce.cgi
it plugs some wheres in the engine bay to where the o2 simulator harness is.
so if your doing a swap and worried about an o2 simulator, just used the ones that came with the k20 (RSX, RSX-S, RSX-R, Civic SI) and add the o2 simulator.
a popular and well recomended o2 simulator is the Caspers Electronics o2 simulator
http://www.casperselectronics.com/cgi-local/store/commerce.cgi
it plugs some wheres in the engine bay to where the o2 simulator harness is.
so if your doing a swap and worried about an o2 simulator, just used the ones that came with the k20 (RSX, RSX-S, RSX-R, Civic SI) and add the o2 simulator.
