Man us Audi drivers are well liked (I've had 2 A4 TDis in the past).
Must say when I was doing that run I would sit the A4 on cruise at about 80 and then back it down with good distance to the car in front, no point in going right up their chuff just makes you more likley to stuff into the back of them.
I always used to find it was the 320/325 that would blast up behind me at about 120, just start to slow as he pushed the headlights out of the sockets then sit there (often with HIDs or other super bright lights on) about 3 inch off my back bumper. I used to just gradually bring the speed down to 60, then 50, then 40 and just watch them explode before dropping it a peg, leaving a nice black diesel cloud and shooting off bond style![]()