Misfiring System?

Can any one tell me what a misfiring system is and what it does for the car.

B/C i was watching Initial D an there was an Evo III with one installed and i wanted to know what it is

Thank you
xlxviciousxlx

MSD fireing system, prbably not a "misfireing" system.... MSD sends multiple sparks to the spark plug, burning all the fuel in the cylinders, instead of a stock system, which creates one spark per plug.