Manifold / Header options for SC set up

The Oily Bits S2 Specific Topics
1

My Exige S failed its MOT equivalent last week due to not passing the emissions test.
I’m running a 100cell 2Bular cat and back box.
The cat is very nice ceramic coated piece with a 3rd bung for WB lambda. It can also be used with both stock and 2Bular manifolds.
The friendly technician at the MOT station said the cat is too small and I would need to refit the original one to pass the test.
My thinking now is if that is true and I anyhow need to refit stock parts for MOT I might as well run a decat. And then why not throw in a different header / manifold when I’m at it.

Question is:

  1. Does it make any sense at all that the cat is too small?
    If it does make sense
  2. What are my options ?
  3. What could be the “optimal” set up for good power ? I’m guessing a 2Bular 4-1 + Decat is a good bet.
  4. Are there any designs out there one should stay away from ?

Cheers
Michael

2

Make sure they got your cat hot enough to be able to work properly before doing the test.

I can’t remember if my cat is 100 or 200 cel? It’s a 2bular one but it needs to be blazing hot for it to scrape through the mot.