yeah, no cats = loudness. i have an offroad h-pipe and 40 series flowmasters (the loudest ones...2 chamber) and it's very loud. i had a state trooper following me around yesterday afternoon with his window down. i was like baaaaarely touching the gas to get home
you'll see an increase in hp with no cats since you're opening up the exhaust more. in my opinion, if you're gonna remove cats, remove them ALL, or none.