They do say that the 'universal' sports cats are illegal on post March '01 cars.. not for road use, stamped as such, blah blah blah..
While I get the necessary to have the front pipe (and manifold) made, I was going to buy a standard front pipe/cat.. about £70, with fitting kit.. do me for a year.
But the type approved are over a ton and I'm a bit too much of a skinflint to go there unless I have to.
We're going to a garage tomorrow, see if they'll put the car on the ramp and tell us where it' blowing.. they might be able to do a £20 fix (in my dreams I suspect)