My A6 has a 120-Amp Valeo alternator that AutoZone has for $180 with a lifetime warranty. LKQ also has used units with low mileage for about $80.
After having to remove the entire front of the car to get the old one out, $190 in labor doesn't seem unreasonable. My wife was a little concerned when she came home yesterday and saw the whole front of her car laying on the floor in the garage, but I couldn't find another way to get to it. By comparison, I recently had to change the alternator in my Dodge truck and it took about twenty minutes.
Sometimes the German approach to serviceability doesn't make the most sense
, but I can't complain too much about an altenator that lasted 240K miles! The brushes in the voltage regulator had worn grooves in the shaft so deep that one of them wasn't even making contact any more and it was still working. Now I just have to put everything back together. Good luck with yours.