I also posted on the trouble shooting sections but I think this sections gets more traffic so here goes.

A buddy of mine from Mexico wants to order the RRM headers but we can't figure out which ones to order. His model number is CY4ASNSHL2CS, RRM doesn't post that model on his website to figure out what to order. Anybody here knows??

 

I'm not sure, You could try and PM or email Rock from RRM and ask him.

I believe the PZEV's have a secondary catalytic converter on the end of exhaust manifold, where it bolts on to the rest of the exhaust. So he could try to physically look under the car at the manifold and try to see if theres another cat up there. I can sort of see it on my car, if you lay down and look up under it. I could be wrong though, I'm only sure mine is a PZEV because it matches those model numbers that identify it.

 

Yeah asking RRM directly would be the best way to go for this. If they can't tell you directly, they probably know who could.

Their contact information is on their website.

http://www.roadracemotorsports.com