I am in the process of configuring/purchasing an exhaust system for a remap that is planned. This is on a 2002 WRX.

Currently looking at de-cat up-pipe, de-cat down-pipe and the shorter de-cat centre section leaving the OEM resonator section leading to the Prodrive backbox.
Then come MOT time putting the last cat back in place between the end of the downpipe and centre pipe. My question is it likely to comfortably pass MOT with just the last OEM cat in place?

OR, is this a better setup...

de-cat up-pipe, sports cat down-pipe (Ninja, TSL or Prodrive), and straight through centre to the backbox.

Noise is an issue for me which I would like to keep as low as possible, whilst keeping minimum hasstle come MOT time, plus getting the maxium gains whilst addressing the first two.

Also, is it the case that if the cat is not 'type approved' it will fail the MOT, or are only the emissions checked?

Can anyone shed any light?

 

Ok, ive decided to go for the sports cat down pipe and de-catted rest, then worse case swap the centre section back to OEM come MOT time. Although, I do appreciate your point.

Is there anywhere in particular to get a good buy on a Sports cat? I take it, its one of those things that's better off not getting second hand?