The YS 63 pressurizes the fuel system, but supercharged? I don't know. It is an engine that I've used in profile/funfly models of about four pounds (OMP Fusion and Edge). It is very reliable, and is more of a torque producer than a high rever. The YS 63 pulls my Ultimate very nicely. (In my opinion the Ultimate is not an ideal 3D toy as it is flown quite a bit faster and has a higher wing loading than is typical for 3D flight.) I think that the OS 55AX would also be an excellent choice for the Ultimate. Pictures of my Ultimate would look just like those found at the Horizon web site, except that mine has no decals as I almost never install them.

Fly safe, Glover