Originally Posted by 
slug_burner
				
			 
			You don't need a Megajolt if you have an MS3, just need something to convert the 5V logic level to something that will drive the ignition coil pack.  I don't know if there are coil packs that can be driven directly from the 5V logic levels.  Maybe a coil on plug arrangement works on 5V levels.
I have an MS2 which has been made to fire the coils from the ECU; they call it direct-fire and therefore there is no EDIS. The disadvantage is there is no limp-home mode; however; one doesn't have to buy an EDIS8. So in answer to your question the coil-packs do not need an EDIS always.
From the Q&A section
b. Will you be controlling ignition timing?
If NO, then MegaSquirt-I™ will most likely suffice. If YES, then an MS-II® or MicroSquirt® (or MS-II Sequencer®) is your best option for controlling spark advance. MicroSquirt® or MegaSquirt-II™ can control up to two ignition outputs,