I would be willing to bet the OP's problem is RFI related. RFI from in the distributor cap is being transmitted thru the pick-up wiring to his digital MSD and raising he!! with it. He is sort of correct with the digital signal stuff but if he shields the wires from the pick-up to the box it should work OK. Had the same problem with my Holley EFI ecm. A Hall Effect pick-up would also solve the problem.

The reason MSD says he needs a crank trigger is because it isolates the pick-up from the RFI and the box then gets a clean signal. If he was half as smart as he thinks he is he should have figured that out before he bought the other box.

Kevin