RS coil pack

[DTSJR]

Sorry if this has been covered before, I searched by only saw an archive post.
I was able to pick up a brand new coil pack made for the Impreza RS's for alot less than list. I was hoping to put this on my legacy to try to get a better spark. I was hoping Id get a diamond coil pack, but lets just say I got what I got. I know the legacy coil pack has 3 plugs, power and channel 1 and 2. The RS coil pack has 4 wires however. I cant find my ignition system wiring diarams for the RS, so maybe one of you guys knows how the wiring is for the coil pack. Im guess one is power, one is ground, and theres channel 1 and 2. Is that right? If so, adding a ground wire should kind of make this a plug and play thing, correct?
I read I could use an MSD DIS-2 to install this, but I dont feel like spending $350 on that yet.