Can someone explain the ECU to me?

I just bought a MSD Blaster 2. The more I read, the more it seems I'm suppose to buy. I just have a stock ECU. Will that work?
Then I read about the "orange ECU" and the "Sliver ECU". From what I read the silver is better.

Now if the coil is sending out the spark what is the ECU doing?

Do you guys suggest a silver? What else is there?

Thanks much!
Author: admin