To do it with no modifications to the engine only requires a sparker system. Before you go out and buy one though, make DAMN sure your exaust has absolutely no leaks, because if it does the spark will ignite the gasses and they may flow backwards toward the engine. Also you could tinker with the timeing to get it to backfire, but im not real sure. That was a great movie by the way, it also lead to more arrests and speeding tickets in 1 night than my town has ever seen. Damn good movie.