I'll give all you GTP-Memebers/Guests/Nascar-Fans my knowledge in Nascar car set up as i have been to the race tracks for 6 years and stepped inside these loud machines lots of times...(Note that Nascar is all about suspension set up since you can not modify the cars)
For GT5 automobile setup for Nascar @ Daytona:
-First off, if you drove your new car (NascarStockCar) before changing the oil first, you have screwed up already, because now, your car will always have 850HP instead of 891HP boost.
(Also note that all of the toyotas get more HP boost than chevys or fords)
-Raise the front end all the way up in height (To avoid losing speed from bottoming out) (Plus, in real life, front height rules of the official nascar rule book state that all cars have a front height limit due to everyone wanting to raise the front end because the splitter does not allow you lower the car without it bottoming out)
-Lower the rear end to -15 in height (To lose drag)
-Camber is unfortunatelly useless in GT5 Oval racing as you can not adjust each tire individually and so one side will not grip and will wear out very rapidly...the other bad thing to camber in one side acting negatively is that it destroys your car set up on ovals if set up higher than 3.9 degrees.
-Spring pressure to 18.5
-Dampers to 8-4F 8-4R
-Set your gear ratios to higher than 336mph if your planing to draft, or 224mph if your going by yourself (Ex. Qualifing).
-ABS set to off
-No traction control.
-Downforce of 35front and 55rear. (funny how in real life, Nascar does not allow any team to adjust the rear spoiler at daytona, but in GT5, you can)
-Set the brake bias to 2front 2rear as youll probably only need a tiny bit.
-And most importantly, Set the LSD Acceleration&InitialTorque to 60 if you dont want to spin out at high speeds on corner exits...Its better than traction control because you dont lose power, but you do lose acceleration on exits of roadcourses with tight turns.
If you have followed this car set up, winning at daytona should be easy because your car/driver can now run 217mph full throttle right next to the yellow line and get away from the pack for easy carrier/online wins. Oh, and dont forget smooth driving when you turn, it really matters.