I like the flowmaster 50 series which is their 3 chamber muffler. Nice rumble yet you can hear when cruising. The 40 series are louder. Alot of people like the dynomax super turbos which are cheaper but have a nice sound. Can't help with the headers.
I've had good luck with fit, finish, and function with hedman and hooker.
Make sure you buy headers for a 428CJ/427 engine. That way you get big tubes that will take the increase in flow from the cam. They aren't hen's teeth either, so you should be able to find them from places like summit, etc.