2002 S8 cat/exhaust - HELP!

[The_Laird]

Now I'm getting desperate! I can't find a 'type approved' nearside cat for my 2002 S8 anywhere and Audi want £740 plus fitting. I've also beem advised by Ben (ex AVP I think) that I should not replace just one cat or there will be 'issues'.
So far, I've had someone offer to get the cat under an earlier registration plate (so the type approval doesn't apply), but A4 Audi (independent Audi garage in Glasgow) say that will trip the warning lights, someone else say that an A8 4.2 cat will be OK (and I can get one on ebay), someone else says don't buy an aftermarket cat anyway 'cos they're rubbish, and (my only hope so far) MJC (I think) in Walsall offer 2 sports cats and a custom after cat system for around £850 (tempting, but I'm in Scotland!).
Jeez, I just bought the car and thought it was great....for a while... but there must be a better solution (although if all else fails, I'm taking a day off to drive 5 hours each way to MJC!).

If anyone has been here before,please pointme in the right direction. Thanks