That being said, if you put a 200 cpi metallic high flow cat on your car it will most likely pass the tailpipe emissions test once warmed up AND it will only fail the visual test if the tech actually crawls under your car to verify the cat stampings.

Can you pass inspection with high flow cats?

Hi, People say you can pass it without CAT as long as the car is tuned. They should pass the sniffer just fine with proper tuning. it will not pass a visual inspection.

Will a high flow cat pass MOT?

The Milltek Hi-Flow cats will pass the emissions element of the MOT test with no problem however they are not tested under the 2009 ruling and hence the 'not suitable for road use ' badge .