Why do not you advise? the sound is better and the dino tests give more hp and torque, the oem exhaust is a great escape, although heavy.

The next step would surely be to remove the catalysts from 400 cells.

Only for the OEM exahaust, not for europipe.

Does this exhaust hack work on a 997.1.50 Oem exhaust
 

Any idea if doing this hack ( adding the inch and a quarter hole to each exhaust) works for the 997. Not a big fan of the current sound but also not willing to invest 4 to 6K in a new exhaust system. Any issues with passing inspection once done. How much louder does this result in. I have had the car for 2 plus years and this is the first time I have come across this recommendation.

I've had my TT for almost 10 years and thought about this hack. I'd first want to buy a donner OE stock muffler for cheap to cut up. I concluded, not worth the trouble. I had a N/A C2 996 for 7 years with a PSE that sounded fantastic and I left the flaps in open mode all the time. You can't get the same sound with a turbo as they chop up and muffle the sound before it even gets to the muffler. My brother also had a 996TT with a Fabspeed high dollar muffler and I thought the sound was OK, not great and he offered it to me for a couple hundred $$ used when he sold his car. I passed on it. When these cars were new and sold for $125K- $165K, well heeled guys with deep pockets would spend $5-$6K or more on an exhaust and another $2K-5K on a tune and think nothing of it, then find out that a totally stock car was worth more when the time came to sell. Just my opinion, nothing more.

It sure will. No issue with inspection since the catalysts are not touched. It won't make a glorious symphony like Europipe or Akrapovic but it certainly helps a lot. I held me over for a while until the car got a cat-less AM exhaust.

Thinking about running a "Catless" Kline system on my 02 996 TT using test pipes instead of the Cats which I assume you're doing. Is the Kline system similar to a straight X-Pipe system or is it baffled/silenced/ muffled in any way/ Any codes on the test pipes?
Thanks for any advise you can give me!@

it's an "x pipe" setup but not loud like straight pipes even when "decatted". no codes when catless that i can recall and still uses the 02 sensors. but - -

long ago i reinstalled the cats when the car was in Calizuela owing to smog testing issues.

the car now resides in a place that has no test requirements but i've kept them on anyway.

my now 10 year old Kline w/ 200 cel cats is sufficiently melodious when "on pipe" and yet i no longer need the few extra BHP that removing them again would net. but i still have my "decat" pipes just in case.

if you do go "catless"? prepare for "unburnt" fuel odor at idle. beyond that?

catless is the best way to go. however, greta thunberg does not approve of this advice. **** her too lol

Thanks for all your first had info. Very helpful! Is there much difference in sound between cats on vs cats off?

Spooling turbo noises are more audible without CATS in my experience, mods in my signature.

you're welcome.

no difference in "sound" - decatted - only "smell"!

I wish the TT could have the C2 N/A exhaust sound that mine had with the PSE. Glorious!