eg6hatch

hi, i am wondering if anyone can explain what a 2 step ignition actually does, and the benefits to it, and if it is worth buying, what brand, or which ignition system do you reccomend, also, i will be running a turbo setup, so i cant have it interfere with that, but like i said, my friend has it on his eg with a b18c5, and it sounds nuts, and i just want to know more about it. thanks.