I also have a DFP, and find I'm much faster with it than with the controller. I set the FFB strength to 8, which seems to work well.
A couple things to remember:
- There is a "dead zone" in the middle of the steering on the DFP, this can be somewhat disconcerting until you get used to it, as small adjustments from centered do nothing, then the steering starts to kick in as you go past
- With the tuning options, you can change the maximum steering angle. Setting it to a higher value (50 degrees) than the default (40 degrees) will allow smaller movements of the wheel to turn the wheels more.
- controller steering is always modulated to account for the input device: when you move the stick from full left to full right, it doesn't turn the wheels 80 degrees in the same period of time (the car would be undriveable for virtually everyone, as most novice pad users tend to steer this way). As such, you essentially have to relearn how to steer in the game since the input methods are so different. Someone on this forum described it as "forgetting it was a game, and drive it more like a real car."
Once you get it down though, the sense of immersion is amazing, and makes for great fun.