Sorry, I have to disagree with you Zardoz -- the fastest car in GT3 is the Pike's Peak Escudo. When you apply all the add-ons for it -- you can have a HP rating of about 1800 or more, and can get the better part of 300+ MPH out of it.
In fact, I have never been able to truely get an acurate MPH, due to the shortness of the track with that much HP!
As far as th settings for the F094/s or h, try this
1. toe and camber set to 0 (like everyone else stated)
2. down force to minimum (also like everyone else stated)
3. drop that sucker to the ground -- it's a relatively flat course with little in the way of bumps.
4. keep original 1-6 gear settings, and only mess around with the final gear. If you mess around with gears 1-6, you will actually take the quickness out of the first 3 gears, and end up not having enough room on the straight to get to red-line in 6th by the end of it. You may find that your freind in this case is that little bit of turn at the end of the straight. If you are not actually racing, you can just ram the gaurdrail at full-throttle. And always go in the opposite way you would normally race.
And as far as the F686/m being the fastest F1 -- just because it has more HP than the F094/, does not necessarily mean it's faster. The gearing in the F686/m is MUCH different than in the F094/. Unless you are hybriding, you cannot make the gears match that of a F094/ -- I've tried, it doesn't work. The F094 has the lightest frame, the best gearing and when you tune the final gear only .2 more than the original settings, you can smash Michael Schummachers record at the Cote d' Azure track. It allows you to get out of the corners quicker than the CPU's, and on that track, you get plenty of speed in the straights. The original course is "Monacco", and there are very few places to pass and even fewer places to get to top speed -- if you can even do it! I pommeled his record by more than 5 minutes, and did it without hybriding, cheat codes or anything on the first try!
Just my honest and tested opinion.