Rich,
I have only seen the high-temp paint come in spray form in the hardware/Wal-mart type stores...
If you do decide to spray onto the area, literally tape up the entire side of the car, and if possible cover the roof of the car too. It's unbelievable how far the fine mist of spray paint will travel. Don't spray directly on the area you wish to paint, instead spray with a constant left-right-left-right type motion from about a foot away.
Do not start spraying immediately on the area you wish to target. After you tape up the side of the car with some plastic sheeting, start spraying on the sheeting (left side, for example) until the stream of paint is constant and then move the can towards the area you want to spray and keep moving past it onto the other side (right side sheeting) and then swing it back again over to the right side (all while never taking stopping the stream of paint from the can). You will have to do lots of "passes" over the affected area, and the paint will build up very slowly, but it will apply very well. If you feel the area gets too "wet" with paint, stop and let it dry. Do not get tempted to touch the painted area! If in doubt, let it dry!
Every 30-50 "passes" stop and shake the can again (shake it very well) for about 2 minutes.
Try doing it in a garage (no wind and dust) and take your time. Remember, tape up properly!
Hope this helps!