don't gut it since you paid a premium for the cats. Just go to a muffler shop and have them cut the cats off and weld some flanges on then have them make replacement test pipes. That way you can swap them in and out. Make sure you bring the X pipe to them by itself because most shops will not cut out the cats on a car.
I have both a hi flow carted xpipe and off-road xpipe from AR. I bought the hi flow xpipe when I bought my longtube headers, then later decided to go with an AR off road xpipe, which I bought from Lethal Performance. Very expensive, over $500 for just the off road xpipe.