k guys im fairly new to the site and i need your help...i have a 2004 civc ex sedan and i have a 2.5" catback and JVT headers. i currently have on there the stock cat and downpipe. i wanted to replace the downpipe and get one of those OBD-II high flow cats from magnaflow. what diameter do you recommened for the downpipe and the cat...the guy who does my exhaust work said i should make both 2.5" since thats what my catback is. or should i go a little smaller and go with the 2.25"??

 

2.5" would make sense since any smaller would be clogging the catback

 

i would go withe the 2.5" myself for a n/a def not any bigger