i'll try my best here at the risk of getting flammed it is my understanding that the ballast has no relationship to the ECU. it is the coil and ballast that must be matched. a 'standard' ECU requires the use of a ballast because there is only one firing of the coil. this makes the amount of time the coil is storing voltage longer and cause the coil to get hot at lower rpms. so, if you are using a standard ECU with an oil filled coil then yes, you need to use the ballast recommended by the coil manufacture. in the case of a Blaster2 i believe the recommendation is a .5. a stock coil i think is a .2. you need to use a .5 with the Blaster because it has way more and smaller windings inside to increase the output and it will burn out. with a multi-spark ECU the ballast is not needed because at low rpms, the unit it causing the coil to fire multiple times and NOT storing it.