Originally Posted by ehancock
Engine and turbo are completely different than the 1.8. The platform causes there to be tons of bends in the exhaust so i'm sure that has something to do with the sound. Stock catback is 2.5" and is the quietest exhaust available for the car cause the mufflers are big and there's no real performance gains in swapping out the stock catback for an aftermarket 3". IMO the best sounding mk5/6 use an aftermarket catted/resonated downpipe mated to stock catback and even then they don't sound GREAT
the mk5-6 use stroked/bored internals that are the same for the mk4 hence you can use the mk5 (maybe mk6 is different not sure) crank as a stroker option in the mk4
also the heads share similar ports etc and can be bolted onto mk4 blocks. although I didnt think of the fact that it has a slightly bigger turbo (k04 correct?)
and the amount of bends would definitely have an acoustic effect.