"Performance" is how much GRIP is available for a given car, which obviously affects its laptimes. See, we can interpret this number as a medley of all factors that limit the speed of the car around corners and under braking/accelerating: the driver, tyres, aero, chassi... so simple and so effective!
Human player has 16384 "points" of grip, so it is fair to give the same ammount to the best driver/car of your carset.
"Range" works pretty much as X-Acto explained, but it tends to be a disadvantage. That's because when range is positive, there's a higher probability that the grip will be closer to the performance value, which isn't always the case of when range is negative. You can find details about this in the SDI forum.
Years ago someone teached me to calculate the avarage of the results of a dirver/car and set it as "performance", while 1x the standard deviation of the same results is a very good number for "range".
You can check my performance packs and see how I did it all. It is time-consuming to get the final numbers for your carset, but it certainly worths the effort.
Edited 1 time(s). Last edit at 08/08/2006 11:56PM by SuperSonic.