contact stu at motorsport developments. he is working on the supply of these.

basically the ecu sends a pulse to the ignition amplifier to tell it to make the coil spark. that is normally done on a cossie 4 times per 2 crank revolutions, and the distributor sends the spark to the right cylinder.

with a coil pack, you run what is known as wasted spark. that means that a spark is sent to 2 cylinders at a time, one of which uses it, and the other doesn't (so it's wasted - apart from wearing the electrode of the spark plug ). but if you were to use the standard output from the ecu and ignition amplifier, the coil pack wouldn't know which pair of cylinders to send the spark to. so you need some extra electronics to get a signal from the ecu that is based on both the crank position sensor and the phase sensor. that signal then needs to go to 2 ignition amplifiers, or a twin amplifier, that then tells the coil pack which side to fire a spark to it's connected pair.