For our average enthusiast, the chalk method is probably adequate. If you are actually pushing limits at an autocross or strip, you really want to look at the tire wear to see what it wants. You can immediately see the abrasion that competition puts on a tread and adjust accordingly. If you want to get a bit more serious, then the temp method not only will tell you pressure needs, but how effective your spring rates are from corner to corner, as well as what your weight distribution demands for pressures.