hi, i was at a exhaust place and asked him to do a full decat pipe on my octty vrs, he told me by doing thiis even if the 02 sensors were replaced in the new exhaust the engine management light would stay on. is this true,

Yup.

yes

sure is

mines de catted and it doesnt throw the engine light up.

The EML can be mapped out if it's decatted.

thank you everyone for your help , i might jus get a cat back exhaust done for now.

i brought a de cat and had a sports cat welded into it worked out £200 cheaper than the miltec downpipe and sports cat

I fitted a Decat downpipe at the weekend, I already have a cell light on from from SAI removal although no performance hit.

So I am getting the cell mapped out for the SAI, so also make sure the Decat is sorted at the same time.

There are spacers available which stop the CEL. 42 Draft Designs in the US do one and so does a bloke called Wayne in the US (Google Wayne's Angle Block)