in my opinion 12in glass packs sound great with or with out cats i put them on my old convertable with no cats very very loud but sounds sick and my causin still get complements on how good it sound and i put a set on my buddies 03 gt with full cats it sounds great he loves it and has 2 more guys that want me to put them in there cars id recommend running tail pipes but thats up to you
mustang notch 4.6 4 valve
