It's a 2001 bug eye, I had a performance exhaust put on 10years ago but not sure if it had a cat replacement on it, always went through mot no prob, I know the garage owner he said he had same problem with his Honda civic and he managed to by pass and tell computer that there was no problem to over come it, that's what he's thinking I might be able to do. Car runs fine apart from I think it's starting to back fire a little bit sounds great but don't think it's supposed to.