I went and got the jr high torque metal gear servo. I did some looking around at many kinds but the best bang for my buck was what I got. The horns I got were the jr 1-1/2 they have a great lock and you run ball joints on them. I will let you know how they work once I fly it. If the s3305 servo works for you thats cool you know they work. This engine is a runner and I havent even run it very long. Anyone know if they make or ever will make a big bore kit for this engine? That would be a great performance kit to add to this fine engine.