I used to have a Marelli in my cagiva grand canyon,( ducati 904cc engine) and it worked ok but with the all known problem, so I acquired a Myecu Kit, BUT!! it did not worked,  Cliff kindly offer to check it for me and once it returned from AUTRALIA!! I am in Central América, It did not work again....
The issue, Marelli is a litle more sensitive and my Crank Shaft pulse  was a litle out of limit!! so My ecu did not worked solidly.
Cure: set the factory gap and voila! Since then my ecu work as an angel.

The signal was increased, the gap was almost 3 mm so I took the spacer out and now is .7 mm.