I am digging the game, playing with a DFP wheel. I will admit that the tires on the stock 370 are total crap, but the tuned version makes up for them.
I played quite a while last night, starting with the stock 370. After maybe an hour and a half, I moved on to the tuned unit. After maybe another hour and a half, I went back to the stocker. On the second lap, I cut off another second off my best lap. Plus, having to go slower, I think I found some better lines for a couple of turns.
One thing I noticed with my wheel setup - the brake pedal was slightly sticking at rest, and that was hurting me on the order of 15 to 20 seconds a lap. I had to take apart the pedal assembly and feed a bit more wire in, and everything was golden after that.
I can't remember my exact times, but the stock unit is in the 1:52 range, and the tuned version is in the low 1:39's, which was good for #488 overall(last night at least).