I finally got a silver on this race just now, after trying off and on for about 4 days. I used the Ford GT LM after trying about all the other cars possible, and tuned it with the original tune provided by s2k2k3. Great tune. I'm never doing this race ever again.
I was the same as many noobs when I first tried S10. I couldn't get past 9th place, even on std physics. So I started looking for a tune that would help me. I didn't find much for std physics. So by trial and error I kept at it and got to 7th, 5th, 3rd (passed!), and finally scored the win in the 111R. That was right before the Spec III update.
That's when EVERYTHING changed. The 111R was a completely different car after the update. And all the other cars changed to one degree or other. The Ford GT which I couldn't drive at all in Spec II, now was much more forgiving and actually fun to drive in Spec III.
The PP levels for the S events changed as well.
So I decided it was the perfect time to create a list of Spec III tunes for the S-class events. My goal was to give noobs a reference to help them clear the events and cut down on the number of "How do I win S--?" threads.
I made the list of tunes you see here (at least the original version of it).
But along the way something I didn't anticipate happened. I discovered that S10 is actually VERY easy (in std physics) in EVERY car that makes 750PP. The race that took me SO many tries to finally get gold I found myself taking the lead on lap 3 and cruising to the win by over 10 seconds.
What changed? Me. I no longer felt the pressure to win (I already had the gold) and so my driving was much calmer, smoother, and FASTER. The race that frustrated me for hours became my favorite "play" event.
Moral is, take some time off from this event, but come back to it without the pressure and you'll find it's much easier than you thought, and alot more fun.