[jdean]

Like Tom, I have a 521 with a C6 (1:1 final drive), but with 3.27 gears. I have a set for 3.08s that I have never installed. No more miles than I put on the car, the 3.27s are fun. Most of the cruising I have been doing is country backroads where the speed varies a great deal, so no need for reducing cruise RPMs. Even when highway cruising at 70-ish it is not too bad, but I bet overdrive (or 2.75s) would help the hearing a bit.