This is a reply i got from the 2stroke shop
"The Ignitech already has a stator setup programmed in for the MC18 so it can easily be done, and has been previously.
Basically remove the PCM unit and wire in the Ignitech.
The HV (High-Voltage CDI coils) coils on the stator are not used, just 12V from the battery/charging system, and the unit drives the std coils and powervalve motor.
I have several friends that have MC18/21 so any real issues could be helped out from this end.
I can help with info on setup etc, but the actual wiring up of the unit would be up to the purchaser."