I'm after a turbo back exhaust system for my classic STi, would like a straight thru system but then MOT's are a problem.
So, if i can run a system with just one cat does it matter which one you remove (the downpipe one oe centre section) with regards to emmissions and power/torque

 

i left my centre section in and passed the mot, its the easiest one to remove and fit. if your worried and can afford it get a sports cat downpipe and remove the centre cat.

 

The classic STI's only have one cat and that is in the downpipe, the centre section just has a resonator that looks like a cat.

Banny

 

So basically i need a sports cat downpipe as part of the system, obviously a bit of sound would be nice but performance above all and must pass track regulations,any suggestions, was looking at H&S but seem very expensive, also looking at scooby world ninja sports downpipe with vortex afterburner and straight thru centre? dunno how loud these are tho

 

Downpipe's the best place to leave a cat in. It needs to be hot to work best, so a sports catted downpipe will do the job.

 

Mines on a k plate hasn't got a cat the mot are a bit more freindly on that year as its the cross over when the new emissions came in
KIPS