Here my advices:
When i started the game for the first time i had massive understeer (had to go mad to steer the car) and massive brake the zone. Moreover very loose force feedback.
so what i did (now it feels pretty good even if i tested just some cars):
- entered the calibration process under wheel option
- rotation setting: follow the instruction for the first step and then when it asks you to turn the wheel 90^ put it in a 90^ position with 900^ displayed below.
- calibrated also the pedal
- increased force feedback to 80% and increased deadzone reduction feedback
- increased wheel sensitivity
- decreased brake deadzone
- increased brake sensitivity
I also found that (and this is mad in my opinion) steering lock and feedback should be adjusted for each car under car setting and it changes a lot..
Maybe reducing the rotation to 540^ (following t300 guide) should allow better force feedback and responsiveness. Rember that than in the calibration when you put it 90^ you'll for 540^ below
hope this is helpfull. i will try to fine tune when playing. please share you setting/issues
However overall there are too many options... they should provide a basic setting working as it should.. really impossibile to mess with all that option without a guide. Bad decision imo. This is the only point where PD dominates. You don't need nothing in GT, just start and it feels right for every car. ..the problem is the rest of the game