2002 A6 Quattro with 3.0 engine. 97K

Been down this road before and all comments are welcome. CEL light is on with the codes in the title screen. I searched the FAQ and apparently the P0741 is something I can live with, although I find that hard to believe. The others are emmision related. Any opinions on going with an aftermarket CAT on the passenger side? I've seen some as low as $420 per CAT.

I had both CATS and OB sensors replaced under the Clean Air Act recall that AudiTech79 as been mentioning over the years, but it's way over the mileage warranty now and I doubt if Audi wants provide new CATS and sensors this time around, so it's up to me to fix this.

Between the CATS and a timing belt, I'm guessing anywhere from $2,500 to $3,000 for everything, but I could be way off.

Finally, any thoughts on changing out the transmission fluid ?

Thanks to all.