Straight through exhaust/mot regs

[Midnightclub]

Ideal for a turbo engine is 18" of straight pipe............. don't need back pressure, you has a snail

it will free the exit of gasses from the engine which should mean that you get on boost a little bit sooner (though it probably won't even be noticeable)

As far as legalities go, as said already, as long as it has 1 box in then its all legal as far as the police are concerned, as for the MOT, they can fail them on excessive noise but that is down to the testers opinion and nothing else!

Edit:- Ruan has answered everything pretty clearly there I would say

My friends 1.8 vento idles at 85 db's MOT on wednesday reported "Exhaust is slightly louder than normal but who can say what excessive is"? Legend !