I'm using these settings for PS3+DFGT. They work well enough for me.. I'll fine tune my settings when my G27 arrives.
- all deadzones: 0
- steering sens: 100
- accel sens: 25
- brake sens: 12
- speed steering sens: 0%
- FF: 10
- turning: 900
Credit goes to amar212 over at GTPlanet.