Thats a great thread you have for us Adrenaline, but for the GT LM
Test car, there is only one tune listed, and they don't have any settings for the tranny.
I'm not a tuner, and I've been waiting for Paulie or Ravenmaven to post their fantastic GT LM tunes for GT5, (hint, hint) but in the mean time I've been playing with this one. You can take the corners at Indy at 205mph. I've recently tweaked the Aero, LSD, and Tranny to the following, but before this I was running the defaults for those and still got golds.
[seemingly great tune]
Hopefully, the afore mentioned Senior Grand Tuners of what I consider the fastest GTLM Test car tunes from GT5P, will be letting us know how to do it right.