I'm tired of hearing this discussed, so here is an end-all, LINKABLE post about the difference between RSX-spec and EP3-spec headers and catbacks/midpipes.


An RSX type-S exhaust will fit a base RSX, and vice versa.

All K20 heads have the same bolt pattern where the head and header meets.

An EP3 can run a header meant for an RSX or an RSX type-S. However, to do so, the midpipe has to be for an RSX as well. The axleback (the muffler, after the midpipe) must be for an EP3.

In order to make an RSX header work with an EP3 catback (midpipe and axleback,) you must shorten the midpipe by approximately 3" and change the angle at which the header and catback meet.

However, K-tuned makes a catback that is specifically meant to fit an EP3 with an RSX header. I'm currently running this, and it bolted up to my RSX header just fine.

Also, if a header is advertised to fit both the EP3 and the RSX, it's meant for the RSX. There's no EP3 header advertised to fit both.

Common EP3 headers are the OBX header and the EP3 specific DC sports header, as well as some other discontinued headers.

Common RSX headers are the Skunk2 Alpha header, the PLM/kidd racing/private label/clubRSX header, the K-tuned race header, the invidia header and the greddy header.