300blackout

What you guys' experiences with catted vs catless downpipes?

Most downpipes for the M178 are catless (Weistec, Agency Power, Eurocharged) and priced betweeen $2000-$3000. The unique feature of Agency Power's catless downpipe is that they are 3.5" diameter tubing at the turbo and taper to 3.0". All other manufacturers are 3.0".

Renntech downpipes are catted at priced at $5000!

So unless there is an overwhelming reason go to catted, I'm thinking of going catless. Can you please share your experiences though to confirm my decision is correct. Thanks

Vic55

No experience personally with DP's but I have heard its almost more cost efficient to just go with the Turbo upgrades as the labor for the dp's is long and expensive.

If you must go DP's then Weistec and DIME are good options at the price point you are looking at (and proven) but the gains are really mostly tq with some peak (not usable hp). Our cars really will have traction issues as you start pushing that much mid range tq so a good set of rubber will need to be attached.

Td33

If you don't have a tune no cats will give you a CEL. If your car is tuned that won't be an issue. Only issue is with your warranty and if you have required emissions testing. No cats will not pass.

sonystyle02

Vic55 and TD33 are right. DPs do increase the tq a good amount though a stock set-up has a hard enough time getting traction as is. Also, a proper install of DPs require the tranny to be dropped to remove the stock cats. Otherwise, a cheaper (though not recommended) alternative is to cut the stock cats out and shorten the install time (no tranny drop). Obviously this destroys your stock parts and if you ever get a state ref, you're SOL. Since our turbos are sitting nice and pretty up top, install is a bit easier.

I recommend reaching out to Dime Racing for your options. They can help with the tune as well to suppress the O2 CEL.

kumizi

I had Eurocharged cut my stock stuff up to install their aftermarket downpipes. This method only took a couple of hours instead of I believe 8-10 hours.

Guilty

I would recommend getting in touch with Dime for the downpipes. I sent Sony there and he seems to be very happy with his setup. If I were to do it again, I'll probably pass on them and get the turbos directly though.

dimeracing

Please let us know how we assist. We have vast experience with the AMG GT and how the car behaves with various modifications. If you also need an ECU Tune to work well with your new exhaust, we would be happy to set you up correctly. Thanks so much.

Dime Racing

emericr

A cheaper option which achieves most of what the downpipes do is cut the secondary set of cats.
Only costs you a few hundred bucks. Fully reversible and no CEL. Just my 2 cents.
I would agree with most that the DP cost is prohibitive and if you are OK with mods potentially affecting your OEM warranty, then the turbo option is the way to go.

RBM113K

Who has the best turbo mods,and are they bigger or reworked stockers ?

emericr

I only know of GAD that does bigger turbos.
I suspect Dime Racing in the US with the rwhp they claim is also a full swap of turbos.
The other tuners currently only provide reworked stockers

RBM113K

Ok thanks

Staff@WORLD

We have downpipes coming out in 2 weeks. What I assure you is the best fit and we eliminate the exhaust donut that every other aftermarket downpipes still uses. We started do this with our newest E63 downpipes and it has worked out perfectly.

Pricing on cats downpipes will be $1950.00 up until the end of the month.

FourT6and2

Donut?

P Rock

Bringing this thread from the dead.. maybe some time has passed and new developments have since occurred.

Some people here saying it's better to just install better turbos. My question is, won't the 4 stock cats still be a bottleneck to better turbos?

I was shopping and researching downpipes for a bit more sound and performance but now I'm not so sure...

dlefty

Yes, the cats are a restriction no matter what, stock turbos, big turbos, etc.....

Kooks Exotics downpipes were fantastic, had the best purest non welded together mandrel bends, unfortunately that business went by the wayside for them and they are done with the “exotic” scene, now I would start by taking a look at Keller Performance downpipes for our cars if I were in the market for stainless, or BRogue Built if after all titanium.

502Bill

Actually, you can still get the Kooks Exotic down pipe/midpipe combo. I bought a new set about 2 months ago. Great construction, however I did have an issue with fitment. I bought the parts from a distributor but dealt with Kooks directly to resolve the issue. I sent the left bank back and they confirmed the down pipe bend was slightly off. They corrected the issue and sent me a check to cover my shipping expenses. Good customer service.

dlefty

Glad to hear they are still supporting after the entity that was the Kooks Exotics seller and Kooks ended the relationship. Win for all!