Having been reading the following link I got thinking whether or not buying an aftermarket downpipe like Milltek or Pipewerx was actually worth it? Reading the tests from AWE, the 2.5inch downpipe actually gave better results with the standard K03 turbo than a 3inch downpipe. I have been thinking of just removing the pre cat from my OE downpipe and leaving it at that rather than spending £500 for an aftermarket DP. I have seen on various other websites where turbocharged cars have been running nearly 400bhp and still only using a 2.5 inch downpipe and cat back system. They only reported that changing to a 3inch system gave more noise and no considerable performance benefit.

What are other peoples thoughts and ideas about the above?

Edited 9 October, 201015 yr by 56OctyVRS

Having been reading the following link I got thinking whether or not buying an aftermarket downpipe like Milltek or Pipewerx was actually worth it? Reading the tests from AWE, the 2.5inch downpipe actually gave better results with the standard K03 turbo than a 3inch downpipe. I have been thinking of just removing the pre cat from my OE downpipe and leaving it at that rather than spending £500 for an aftermarket DP. I have seen on various other websites where turbocharged cars have been running nearly 400bhp and still only using a 2.5 inch downpipe and cat back system. They only reported that changing to a 3inch system gave more noise and no considerable performance benefit.

What are other peoples thoughts and ideas about the above?

well the standard pipes are ony 2.5" so id ignnore them. miltek went for 2.75" on the k03 and 3" on the k04. however danGB is running 390Hp off a 2.75"miltek. whilst the difference between them is small. there is no doubt thatyou will be able to flow more exhaust gases easier with a 3" system. the piipewerx 3" dp sound ace on mine and produced excellent results

me personally id say you need to increase the bore over standard to reap the proper benefits, but i also like the idea of removing the precat as that is a hug restriction