You can do just hte MSD, the coils are to difficult. Since they all have 1 post, and we have 4 cylindres we would need 4 coils, lol. We get away with 2 in ths stock system because they ahve two posts, and fire two cylinders at once (one is in the exhaust stroke, its known as a "waste spark system" for this reason).
If you decide to do just the MSD ignition, you need the DIS2 model, which retails around 320 bucks. Money better spent on other mods until you get into the 11s at least.

I'm at the point where I might have to start looking into this, but I've been making it work thus far with stock ignition, right down to the wires and plugs. I do have the occasional misfire though, and it may be time to upgrade. I owuld take it on a case by case basis and not upgrade until you need to, or have more money than you know what to do with.