CH
While not having used one myself, I have spoken to 2 or 3 guys who said the CH was the difference between chunking the motor and keeping it. Frank Tiano is among those that uses it as well.
The 250 does not seem to experience the same ignition failures that the 150/180 series does, for the most part, for whatever reason.
Adrian at CH seems to know his stuff and has been helpful every time I have ever asked on non Moki related ignitions.