Just want to add my experiences here. I've got a PWR122 supercharger (10psi) and cammed LS1, running a full DF system, inc. cats. I haven't taken them off yet, but there is no doubt they're shot to pieces. The thing barely rev to 5000, it's down on power, it rattles like crazy and it stinks to buggery. Let's just say, I've just emailed the guys at Sureflo

Don't get me wrong, I rate the DF stuff - good sound, good quality. But the cats are rooted. FI definitely puts extra strain on them. Just my 2c.