I was wrong on my math about a 100 only being .01 bigger, it actually .09 bigger. According to horizon website a saito 100 has a displacement of 17.2cc where the Saito91 has a displacement of 15cc

I really can't see 2.2cc making that much of a differance. If I didn't already own a Saito 91 yes I would buy the 100 just for the little extra power. But 2.2cc is not worth $270 dollars for me to buy another engine. To get may a few hundred more RPMs.

I might just have to move up to more nitro to get a few hundred more RPMs. Since 15/16fuel is $15.95/gallon and 30% is only a few dollars more per gallon it makes more since to me that I can buy alot of 30% nitro for just pennys more a flight to get the extra power I need.