Roe will send you the kit with or without high flow cats, I would go without if you can. Be warned though, those that have say it does smell a little bit when you are stopped/at idle. Heat within the sills we be better without the high flows, but event he high flows are better for heat than the stock cats.
All I recall is the stock exhaust was way to quiet. With the high flows it is louder without being to loud. I guess that is another factor for the cats, if you do not want it to loud keep the high flows on it. I have a 04 SRT Ram, long tubes, no cats, Manaflow and a Roe SC on it, amoung other things, and it is LOUD.