my buddy with a 94 teg rs has had some probs with what i think he calls "hot starts". the car doesnt even crank over when, just like you said, its hot outside or the car has been sitting in the sun. i dont want to overly generalize your prob, but you may want to look into some sort of electrical fault that was pre-existing in the chassis.

it seems to me, and im not too familiar with the intricacies (sp?) of turbo electronics, that any intermittent type of prob would not indicate hardware malfunction, but rather an electrical or programming issue.

either way, i hope you get it worked out man. GL.