Leave the cats in there. I bought a catless bassani x and left it o/r for only a few weeks. It sounds good without cats but is way too loud. Couldnt even hear the blower wine at all. Went on ebay and bought some magnaflow cats, put then on and the sound is awesome. Not raspy just clean and sounds pretty exotic. And it still sounds mean as hell, I get many compliments on the sound.
If you have no baffles and decide to take your cats off your bassani x, which I just did, it sounds great idling, sounds great while you are cruising around, but at WOT it destroys the sound of the exhaust. It is hollow and raspy and just sounds like a camaro with cut outs to me
Will be putting my cats back in or finding a replacement cb