I've got the A6 Avant Quattro 2.8V6 and the cat (or some similar exhaust component) has failed causing a rattling like noise at low revs. Local service place has just MOT'd it and it's passed the emissions so their recommendation is to leave it until the noise gets worse/annoying or the next MOT comes round. Obviously replacing the cat can be expensive.
I've had a look around to see whether it's worth replacing the eight year old exhaust system with an after market system but I can't find a single off-the-shelf system for the A6 2.8. This leaves custom made units and their obvious cost overhead. Southampton Tyre Services (registered dealer for powerflow) have given me a finger in the air quote of 1-1.2k for a cat back system including the cats.
So my question is:
I live near Newbury, West Berkshire in the south of England. Are there any places locally worth visiting for a custom exhaust system? Is it worth replacing the stock pipes (which have a fair amount of surface corrosion but seem to be solid) or just replacing the cat?