No cats
 

So far I've put on a catless Gruppe-S header & overpipe. I've got the quiet rumble now and would like to liven it up a bit more.

I don't have to have a cat where I live. Should I ditch the second cat for a straight pipe with the stock rear muffler? Or would I be better to replace the rear muffler as well?

Basically I'm wondering if the next restriction to replace after the header & over-pipe is the second cat or the OEM muffler?

Correct me if im wrong (someone else) but replacing the OEM catback would probably liven it up way more than making your front pipe catless.

Edit: actually im 100% sure replacing OEM catback would make liven it up more...

2nd cat doesn't impact exhaust that much as one in header (which you removed by getting catless header), which was the main performance killer. I wouldn't expect much from changing frontpipe's cat to high flow one and i wouldn't want to eliminate altogether unless it's race only car not used daily thus not having to deal with MOT inspections and alike. You may get some on top of catless header gains, but it will be minimal. What you'll get certainly in fully catless exhaust - it will be much louder.

catless front pipe will add a little more sound and little more power. catback will give you the biggest difference in sound. really depends how loud you want to go

I don't want to go too loud, just want a nice rumble and to be able to hear it when I put my foot down. I suppose if the second cat isn't much of a restriction and makes it too loud without it, maybe I should just leave it..

Perhaps I'll just get a 2.5 cat-back and see what it's like and I can always cut out the second cat later.

It all depends what you go with, man. N1 style with single cat is louder than my full catless Perrin. By a quite a lot. I would imagine the stock CBE might get raspy if you delete both cats, too, but I can't confirm.

Whatever you do don't make it sound like this guy's..

[ame="https://www.youtube.com/watch?v=EwdEQ-9_gHo"]Scion Fr-s Borla UEL header w/Straight pipe (THIS - YouTube[/ame]

sounds great IMO.... for a race car

well since I'm in NZ I've got cheaper access to X-Force products than US ones. I guess most of you have probably never hear of them?
http://www.xforce.com.au/bolt-on-sys...0/vid-99002065

I've been told 100CPSI cat won't make much of a difference over the OEM one. So for me it would either be no cat at all or leave OEM cat there with a cat-back 2.5 system.