YOu are running a series 4 blower with 3.73's so you are not going to miss any backpressure as you are making some nice torque and are geared. If you want it loud and don't have to worry about emmissions then go for it without. Ultimately, some cars depending on the tune run a bit better with cats. If you do cats, just make sure you spend some money and get the Bassain stainless ones.
I already hae the Bassani stainless cats so I was just wondering what it would be like without them. I think I'll stick with the cats in place as I find the Bassani a tinge loud as it is.