Remember, 3rd gear in the A6 is 1.53 not 1.00 like the A4. So the A6 is already like an A4 with a 3.92 rearend (2.56 x 1.53). If you go with a 3.73, that's equivalent to an A4 with a 5.70 rearend. The only problem is it will make first gear almost unusable. In my opinion I think GM got it right, great acceleration in the first 4 gears and great gas mileage in 6th. However, if you want more gear, don't go above 3.15 that DTE offers. Come to think of it, you can't anyway since nobody makes aftermarket gears except DTE.Yes, a nice stall, 2800 converter will really liven a car up off the line. Both would work even better. With an A6, I'd go for the 3.73 gear.
That setup is ABSOLUTELY reccommended for your car .AS a matter of fact , it is mandatory . I am guessing that you are making about 20 RWHP more than me , trust me , the 3.15 will bring out the beast [ if that is what you are wanting ]. First gear is not useless , as some people think . In fact , I now look for opportunities to use first gear . You will not be dissapointed .Since not many know about this setup i will give Phil a call a DTE and see if his 3.15 gear would be reccommended for my car with the mods i have already in place.