There are two downpipes that come from the turbos (one on each side to each turbo) and each stock downpipe has 2 cats (so the car has a total of 4 OEM cats). The AWE downpipes replace those two OEM downpipes, and uses just 2 high flow cats (so reducing the number of cats from 4 to 2, and the 2 new ones are high flow 200cpi ones made by HJS, a German cat company).So I'm a bit confused on what the products are here. On AWE's website, it lists a "performance exhaust" which is $2600 and a "performance catalyst" which is $5k+. Are these 2 the same sections but one has cats and the other doesn't??
Which one are you selling? The non cat one? I'm used to cars with just "headers" and "exhaust" for things we can upgrade. Now there's downpipes and x-pipes for this car. Is this a turbo thing?
The X-pipe is a separate piece that goes from the downpipes to the tips (does not include the tips, but you can reuse the OEM tips). The reason it’s called an X-pipe is because it joins the two banks of the engine (since it’s a V8) together, then splits off again in the shape of an “X”. The X-pipe also contains a muffler to reduce sound.
The OEM X-pipe is the quietest, the OEM Sports exhaust is just a replacement X-pipe that is less muffled, and the AWE X-pipe is even less muffled.
However, just changing the X-pipe gives minimal performance improvement since the restrictive cats are still there. Changing the downpipes (and thus the cats) as well gives a pretty decent performance increase AND sounds the loudest due to the increased flow.
I believe the pricing on AWE’s website is for either the downpipes OR the X-pipe (ie the more expensive option does not include the X-pipe as well).
Note this the same on other high performance V motors too - my M3 (e90) has the same thing. Headers off the engine connect to X-pipe in the middle and then rear section with muffler. The difference is that on the M3 the cats are built in to the X-pipe. Inline motors typically do not have an X-pipe since the header has already joined all the cylinders together.