Okay, here's a tune that in all honesty does improve the handling of this car under throttle... to a degree. Some things in this tune are going to look a bit radical, however I have some points to bring up in my defense.
First off, there is no miracle tune that is going to change what this car is, a 922hp beast that only weighs 930kg. Having said that, I think that PD's rendering of this car is not entirely true to its real world physics, that's just my opinion. And the point here is that this is a car that will always demand your respect. The 908 is not a car that you will ever be driving using the throttle like an on/off switch. While this tune does improve the stability of the car under throttle, it can still get away from you very easily if you don't respect it. I tuned this with no TCS, and for anyone who's not like myself and bent on only using ABS=1, I suggest you turn it TCS on, at least to 1.
Back to the tune - I did some things to this car that I haven't done to any others in such a degree before, but like I said this car is something else. And in my defense regarding the toe settings you will see here, the reason they are set that way is because I just tuned the Ferrari F10 '10 car with successful results, and that car comes stock with a -0.50/+0.50 toe setting. It makes sense, because that car is even lighter, and still running over 710hp, so that was the idea behind this tune, and I believe it was to a degree of success.
Aero: 60/85
Trans: 242/249 (try both)
LSD: 19/52/15
Height: -22/-22
Springs: 10.3/10.7
Ext: 7/9
Com: 6/9
Roll: 5/5
Cam: -3.0/0.0
Toe: -0.20/0.66
Brakes: 8/5
I tuned this car at Nürburgring GP/D, which has plenty of opportunities for you to push the throttle too hard and hit an instant donut. My fastest lap was 1:17:525 with room for improvement. You really have to watch your braking with this car, because for whatever reason this is now the 2nd car in a row that I've tuned which weighs under 1000kg, and yet still has problems with efficient braking distances. You would think a brake balance of 8/5 would be sufficient, but I really had to watch my braking points before hitting corners with this setup.
Try the tune and see what you think. I promise no miracles, but hopefully this can help to make the car a bit more manageable under throttle. Again, it's still the same monster under the hood, so make sure you still keep the throttle tamed, and hopefully you'll see some improvement.