I just picked up an Audi A6 Avant 2001 with under 100k. It's in great shape, but the check engin light is on. The owners tell me it needs new cats because they had the alternator go out, and it "flashed" taking out the cats. I have never heard of this, but the price includes 2k for replacement I found a site with good prices for CA vehicles: http://www.convertergeek.com/epcstar...=convertergeek
Should I even think of doing it myself, or just pay for the work?
Do you need to run premium gas, or can you use mid grade of regular?

Thanks for your help, Sebastian