Hey guys,

So, I just installed my ZZP header and downpipe combo. It was used, and apparently a earlier generation. It's around 2.5 tubing and has 2 bolts on the header to downpipe flange instead of the new 3 bolt style. Long story short, it sounds like ass. It is mated to a GMPP Performance catback, and Injen CAI. It sounded great before, but horrible now. No apparent leaks or anything, but I don't know 100%. It's a catless system, but I need a cat for inspection anyway. But it seems like alot of the rasp is from there being no cat. Is the ZZP header combo really THAT loud? Or is it just because of the lack of cat? It gets really loud when you're on the throttle, and above 3k on the highway. But still seems less droney than before, even still. So, I'm going to have a cat put on tomorrow and have them look over everything. Is there a big difference sound wise between a high flow cat and a normal one? The only one they stock are standard ones. I really want this quieted down. Thing takes off now.. lol Also, can anyone validate the dp size exactly? Any help would be greatly appreciated.

Thanks!!