Saito 100 -- $279
CH ignition -- $119 ... This is close to $400! Not to mention the added weight of the ignition and battery and the loss of power going to gasoline!! Sure, it's do-able, but at a significant cost and questionable benefit.

Just put a $179 TT FS .91 in it and be done with it... Spend the rest of the money on fuel and you'll still be ahead 10 gallons later and the plane will be much more enjoyable.

Save the conversion project for something in the 1.20 range