To answer your first ?? about the CAI. Yes, it is neccessary because a CAI is going to suck a hell of a lot more air into your intake manifold. The M50 manifold is a great idea, but before it gets in there it has to go through your throttle body. So check out the dinan website and look into a bigger, bored out throttle body to allow more of that air into your engine. I imagine your exhaust is going to be catback and that will just bolt up just aft of your cat. No big deal, easy install if you can get it up on jacks. I personally have an AA exhaust and love it. The header question I'm not sure what your asking....so good luck!
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