ReaperHWK

I'm all stock besides the CORSA sport. It sounds nice but doesn't roar like I thought it would. From research it was supposed to be one of the loudest.

I even ran the car with the catback removed still not that loud.

I'm going to do Kooks and mid-pipes next, but I really want to run cats because of the smell mainly.

Would kooks, catted mids, and CORSA sport be loud or do I really need to run catless? How much volume do the cats cut down?

RPM WS6

iTrader: (3)

Sound and volume are mostly subjective things, but if the following is true for you:

....then it will likely never be to your liking if you leave the cats in place.

Adding headers alone (all else equal) won't do much to increase the exhaust note volume at the tail pipe. In fact, the improved collector merge of a good LT header can work to smooth the exhaust note (making it seem a bit quieter, though this can also be subjective). Headers are much thinner walled than most stock exhaust manifolds though, so general engine noise (especially under the hood, but also as transmitted through the firewall) usually increases.

Cats have a pretty drastic effect on exhaust note and volume. If you find the system too quiet even with the entire catback removed (as you've mentioned above), then it's a pretty safe bet that no catback system combined with cats is going to be loud enough for your goals, whether you install headers or not. When you delete the cats, the exhaust note becomes much more sharp, in addition to a general volume increase. Some of the aftermarket cats that use a metallic core might have a different effect on sound, I honestly don't know as I have no experience with these myself. But any cat is going to somewhat mute and smooth the exhaust note regardless of the catback used, and regardless of installing headers or not.

99Silver6.0

iTrader: (2)

Ditch the cats and that Corsa tone will come through LOUD AND CLEAR!

2ToeRacing

iTrader: (5)

I had SE and long tube headers with their true duals (no cats) I needed earplugs and it was still to load FOR ME. SLP has a loudmouth system that's just pipes, no mufflers....way load

Reaper_HWK

that’s what she sounds like.

Tramminc

You might want to have your ears checked, that's loud and under load (WOT) I;m sure it's louder.

Reaper_HWK

It sounds good but at idle and Normal driving to me it sounds close to stock(way better tone though) At throttle it sounds good but I want it louder. Even my wife doesn’t think it’s that loud. I’m definitely doing kooks longtubes next I think. I just wanted to know if I really need to run no cats. Looks like I may.

My basis for comparison is some other cars I hear that you can hear 2 blocks away when they go WOT and you feel it in your chest at idle if your behind the car. Half the mustangs around here are twice as loud as the gto as she sits. Lol

So headers and mid-pipes, if it’s still not loud enough then maybe I’ll run straight pipes with no mufflers but the drone must be horrible.

Tramminc

I had kooks headers, 3 inch pipes to vibrant (2) resonator and 5 year old corsa touring muffiers, no drone and I rattle the car behind me. Now I have (4) 3 inch resonators, it toned it down some unless at WOT, still no drone.