Read all you can find about it. it's not the easiest thing to figure out, and it does need some modifications to your car. Another possible idea for you if you're looking for a different engine managment computer is to go with a late 80's Z31 ecu/harness swap. You can get rid of the MAF in favor of the MAP sensor. It's a more modern system than stock and there's a few people who've done it too. the advantage over Megasqirt is it's not all DIY. But hey, maybe you'll like the challenge. The timing wheel is the hardest part of setting up MS.
Ummm you still need to use the CAS if you are using the 82/83 dizzy to trigger for spark.
Now if you go with a Ford EDIS wasted spark setup then you get rid of the dizzy which allows for better FMIC piping in the engine bay. All you do is get / fab a block off plate where the dizzy goes to keep junk out of it.
Not the turbo dizzy. It is built into the dizzy. You will also need to use the oil pump shaft from the turbo dizzy as well. You are correct in that if you use the ford edis then you need no dizzy at all.
From my reading,you do not need a timing wheel . The whole point of using the Turbo dizzy is that you don't need a timing wheel. I was told when I ordered my unit,that you could do away with the wheel by using the Turbo dizzy. I got this off the DIY site.