its ok i got the answer from another forum
If you didnt understand then you should ask and i would explain
An MOT is a test that is done on every car (if older than 3 years) in the UK to prove that it is in a road worthy condition, one of the things they test is emissions
This is where the CAT comes in
A CAT is a catlyic convertor which cleans exhuast gases as they go through the exhuast which results in less emissions
I have a de-cat which means the cat has been removed and a straight piece of pipe has been put in its place
And yes i could measure it my self as you say
But how the fuck do i compare it against some things else if i dont have one to measure
I thought you guys had CAT's in the states as well ?