You're paying $400 too much... but hey if you convince yourself it's worth it, more power to ya. The SD/SSAC headers a 1-3/4'' primaries. Band clamps are cheap. You should use RTV at all slip joints, and how often are you really going to pop your hood and be like, look at those awesome looking headers that I spent three times as much as I needed to spend on...

It's your money though.