I have a 1999 Audi A6 Quattro avant 2.8 V6 and need to replace the main catalytic converters. I live in CA so most replacement parts will not pass emissions. The estimate to fix this problem is around $3,000. Any suggestions on a cheaper way to do this – or where to find a converter that will pass CA emissions? Thanks.

 

Try asking around the forum if anyone who modded their car will sell their stock cats.
These darn things are expensive from a dealer, and in CA you do not have much of a choice.
Alternatively you can go out of state and install 3rd party cats with the O2 sensors where they are supposed to be so you won't get a CEL.