I want to get an Skunk2 Mega Power Exhaust System for my Acura 03 RSX (Base Model) part no. 413-05-1563. Does it come with Hi-flow cat? And also do you need headers and CAI before putting it on, because I already have AEM V2 installed. So does it matter if I buy the exhaust system and then later buy the headers for it?
Above answer sounds good. If you have front brake replaced just make sure its not as tight as rear brakes. Use rear brake and not front brake only. It can flip you and beleive me road rash is NOT fun. LOL
First no it doesn't come with a Hi-Flow cat but you can buy one your self aftermarket that will match up no problem. CAI and Header are never needed to pair up with an exhaust but they do help in the end. They create a full free flowing exhaust path but they are not needed for your set up. Honestly the best set up for your car would be to just have the CAI and the exhaust, don't worry about the header. Having the header will make it flow more free but since your engine is N/A you need to have some back pressure to keep up the power and torque. Also if you buy new header you are going to sacrifice either your low to mid power band or your high power band depending on the type of headers you get 4-2-1 or 4-1. But over all to answer your questions, no you dont need those to use any aftermarket exhaust.
Sounds to me like you have a perfectly running HD.