Heres the rule book guys
http://www.scribd.com/doc/93838596

What counts as a goal? When the ball 100% over the "goal line" or more than 50% or...?

100% past

I do not see a rule regarding a car with massive damage/rolled over/burnt clutch. If a car is disabled, may he shift+P and quickly re-join or is he out of the match or...?

Yes but at ref digression

players may reset at stoppages no?

players can reset at the end of the game/ot or if they ask admin first, goal keepers can reset whenever needed.