[srt2sti]

I am going to get the cobb A/P with the full exhaust and was wondering whether I should go with or without a cat. How much power will I lose and does it really matter since mods are emission illegal anyway. By the way, I live in Cali.

What are the advantages of both?

Thanks.

[srt2sti]

Thanks for the response.

[Nixlimited]

I am planning on going catted for noise and boost creep issues.

[drdome99]

I went catted for smell and emissions testing every 2 years.

[JJ18Sniper]

Kept the stock 3rd cat, it eats up all the smell and still lets me run stage 2 Maps. Don't regret the HP lose at all, no smell and can still pass visual and possibly the sniffer in NY.

[Mach1STi]

from owning mustangs with no cats..this sucka was gonna have one...the smell is awfull...i would smell like exhaust everyday...screw that!

[ValvetrainEngineer]

It kills me when I'm driving behind a Honda civic stinking up the place with no cats. So he went from 120 to 124 hp, big deal!!! I can't imagine how loud it would be without a cat, mine's loud and annoying enough as it is. At least now my neighbor is stealing the attention, he must have dropped the muffler and cats on his Neon - and incessantly revs the engine backing out of the driveway. Drifting a bit off topic now...

[na-STi]

So if the difference between catted and non-catted is only around 10hp, how about getting a non-catted DP with the stock catback? Getting an aftermarket catback only yields around 10hp also, right? I figure skipping the aftermarket catback will save me around $500 and if I get a non-catted DP I yield the same hp as a full TBE w/ cat (plus I save another $100 or so by getting the non-catted DP).

BTW, I only plan on going AP stg 2 and stopping there. I also hate loud exhausts so I like the idea of keeping the stock catback.

[ValvetrainEngineer]

10 hp seems like a bit much. I've heard 3-4 hp difference between no cat and a high flow cat (like the Helix).

[drdome99]

3-4hp out of the box ~10hp if tuned in with engine management

[SAMMYBOY]

I am running stage 2 and a catless DP with stock catback. The noise is just a bit louder with more bass and I really like the setup.
I also figured that the extra little HP lost by not having a catback would me made up by having the catless DP.

[GregB]

I actually asked the exact same question when I e-mailed Cobb. Their answer was that they believe their Catted DP will only lose about 1-2hp over their racing DP.

[JKonquer]

i know you guys think that cat and catless doesn't make difference in terms of HP.
However when they tested the hp difference between cat and catless on turboxs rfl-ti tbe and the result was 8 whp difference. i must say that's lot of hp. and with cobb stage 2, the difference will be much greater than tbe alone.
that 8whp is like having adding intake on your car.

And in terms of sound, it does make world of difference. You don't really hear the boxer rumble as distinct as catless.

As for the smell, you can't really smell it in the car. It will smell when you are close to the muffler, but you can't tell just being in the car.

As for the emission, txs tbe has switchable pipe from racepipe to high flow cat. it will take 30 mins to switch it at the max. So when its time for smog check, just switch it and go back to race pipe when you are done. high flow cat cost about $150. and race pipe is only $90

Only problem i have with catless is the exhaust crap that kept making stain on the rear bumper. You can wash it off with wax or polish compound, but it just looks bad and pain in the ass.

but other than that it sounds great and performs great.

[RacerXS]

I have the Invidia catless DP & Evo II from DP back. I don't notice any smell, & the sound & power is very nice w/the Evo II. If your not scared of the Law hastling you over emissions, I say go Catless. My inspection is good till 2008 in NJ....

[0bluesti4]

Originally Posted by JJ18Sniper

Kept the stock 3rd cat, it eats up all the smell and still lets me run stage 2 Maps. Don't regret the HP lose at all, no smell and can still pass visual and possibly the sniffer in NY.

I thought STi only has 2 cats and both are located on the DP. So your only options are:
1. remain stock and keep both cats
2. get DP with one high-flow cat (from what I have read this won't pass smog in California as 2 stock cats barely pass it as is)
3. get catless DP, which is illegal and if cought will result in your car been impounded

That been said it sounds like stage 2 is no go for me since I am in Cali...pity