From the CAT back, scorpion, 3.5" or 4" (note quite sure )

Cheers

 

More info needed, like age of car. My car passed witha full decat from turbo due to the age of the car (old)

 

from cat back implies you still have the cat in the downpipe (if we are talking classic shape) therefore it should pass no problem.

 

Material the exhaust whether it be mild or stainless steel is not rellivent. As long as its not blowing and can meet immision requirments thats all you need.

 

unless it is already on the car i would think twice about getting such large diameter pipes - 3" should be ample

 

Its a 53 reg STI - only mod is the exhaust from the CAT back - original downpipe still on car.

I thought the noise levels could impact on passing the MOT?

Cheers
R

 

You've said it will be 3.5" or 4"......this is likely the size of the tailpipe (the bit you see), and it won't run that diameter all the way to the cat. The bore size of the pipework is likely to be 2.5", or 3". APS are about the only company that make a larger diameter pipe, but it is only really of advantage when aiming for silly power levels.

Although it will be louder than standard, it is highly unlikely to fail an mot because of this. It would have to be disgustingly loud, i.e. full decat with no baffles to upset a tester enough to fail it.

 

Thanks

Mind is at ease now for a while.

R