I am goin to buy a Cat-back soon and would like to know between the flows and the hooker which is deeper. ive read other post but no one was clear. also ive looked for a american thunder system for my car but the flowmaster website has one for dual cat's or single cat. and the single cat is for the high output engine. i have a 89RS 305 LO3 TBI. so do i use the high output thunder for my car. also what is the difference if i bought a american thunder or an 80 series. is on deeper. all im looking for is a nice deep sounding muffler.