Brought the S3 over a year ago with a full large bore Milltek on (awesome sound

Taken it to an indepenedent and seem to have a few options.
1)Milltek will re-weld for free but will cost over 200 pounds to refit and no gurantee it wont fail again.
2)Buy a new cat at half price (300 pounds) and fit with 2 year warranty.
3)Find a original S3 cat and fit that instead of the Milltek (looking at the part numbers i think this is possible) but loose the performance and sound

I think Milltek are being pretty fair as I have no proof of purchase so might fork out for a new cat but it is still alot of money, even at half price!!!
Pete