I had a 4*60 and over powered it with t Mag 91 four stroke. I used Futaba S3151 digitals all around. Like MinnFLyer said, the standards are fine. You don't really need the speed or torque for something like the 4*60. It you find yourself needing a tad more, put in a 6V battery. I will cut your flight times some, but I've yet to run down a battery at the field. I have a couple planes with the S148 Futabas also. Perty much the same as the S3151's but analog vs digital. The only difference I've realy seen is that they don't "home" as accuratly. It may be that they are well used, but other than that, they function well.

Don