I currently have the 2 inch cores and a stock headpipe with the Cat taken out by Fulsac. Not the re-bar style removal. (Fulsac does not do this anymore). I went with a SERT and Stage 1 A/C. My Tech Dynoed the tune and was impressed by this set up. The bottom line numbers were as good as any High Dollar True Dual exhaust system.
The removal of the CAT cooled it down significantly. I was lucky enough to get the CAT removal, if not I would have gone with the X-Pipe as well.
Kudos to Fulsac