My only encounter with an automatic fire system came from a friend I was crewing for several years ago. He drove a Formula Atlantic car and got into a minor accident that sent him off course through some rather rough terrain. The bouncing set off the fire system like an air bag. Our weekend was done as the motor sucked it fire retardent through the carbs, destroying a $30,000 engine, and, worse, he got second degree burns from the propellant spraying his groin. The nozzles were located at the recommended areas and the system had been professionally installed. Had there been a fire, none of this would've mattered, but there wasn't...only a bent rim and some cracked fiberglass. To me, they're not worth it.