hi all, im confussed. in nr2003, the cts or cot cars, on tracks like cali and michigan, i read to be between 8500 to 9000 rpm at the end of the straights. is this running by yourself or running in the draft? which one do i configure for ?....thank you

This is wrong as far as the CTS physics are concerned, their power peaks at 8000 RPM and therefore 8500 or even 9000 would be too much on a large track such as Cali. If you expect to be in the draft during the race, set the gearing up for drafts.

If you actually use cup physics, their power peaks much later and the difference between corner and straight line speeds are bigger, so you want to rev them close to the limiter in qual trim (to have some power coming off the corners), and a few hundred RPM lower in race trim to keep the temperatures down so you can put more tape on the nose, which is more helpful than a few extra BHP.

ok, so about 8000 for cts and about 9000 for cup for big track ? smaller tracks i can run max 8500 for cts and about 9000 for cup..right?

At the smaller tracks (I assume that we're talking about 1 mile or less?), I actually try to use the entire rev range in cup cars, at many tracks I hit the rev limiter at the end of the longest / fastest straight which means 9200 RPM.
I'm not quite sure about trucks, as I don't race them. At Martinsville you'll probably want to rev the engine even higher as your revs drop to about 4000 in the corners, whereas 8500 (or even less) sounds like a good idea for Dover where the corner speeds are closer to straight line speeds and where adding some tape would be more of an advantage than at Marty.