i have a ls vtec with jdm 4-1 itr header/b16head/ctr cams/pistons,65mm tb , custom magnaflow catback i was wondering or trying to get opinion my exhaust sounded tight without the highflow but now you can't really here now that i have the highflow cat in there is it because i have no backpressure with the oem cat out while performance be better with or without the oem cat do i need the back pressure . i have not gotten it tuned yet but i want to get some opinion somebody has tried i will post an audio clip of exhaust with high flow