Finally won the GT-R race, left some time out there as well and finished .5 seconds ahead... below are my settings:
Downforce: 22
Tranny: 168 top speed
Torque Diff: 20 / 80
Suspension:
-20 / -20
15.2 / 11.0
7 / 7
4 / 4
7 / 7
Wheel alignment:
2.4 / 1.2
.14 / -.10
Brakes: 8 / 10
The car handles more like an FR now and the 4WD understeer is gone.
Had no trouble with RX-7 race, I just love how that car handles and I like Deep Forest as well. The CR-Z was the easiest by far, passed the leader on lap 4 and won with 5 second advantage. I've gotten 3rd in the Challenger event and should be able to win with some smoother lines.
The impossible race however is with the lawnmower powered Fiat

best result is 2nd and 2.5 seconds off 1st, I just can't squeeze any more speed out of that little car. In practice I can run laps that are fast enough, but once my line gets interrupted by the AI drivers I'm toast. The car handles like a dream but the smallest mistake is amplified since its so underpowered.
I see they have added MORE Seasonal Challenges, wonder how often we'll get updates? I think every 2 weeks would be perfect, keeps interest up and forces you to drive a wide range of cars.
Since my parents are in town we had a shoot out between the non-gamers:
my 70 year old father finished first, my wife took second and my mother was lagging far behind. They all seemed to enjoy driving with the wheel once I turned the FFB up to 10, I drive at around 3-4 but they said it was "too lose" like that.