Dears,
I bought the GB Extra 330 ARF, and my first option for the engine is the DLE 55cc from hobby City but I really don't have any experience with gas engines and I don't know if this is a good engine or not, there's good reviews for the DL50 but this one is still new, also will this engine be so big for the plane? another thing; why this engine has a low RPM (7500) less than any other 50cc engine?

My second option for the engine is the Turnigy HP50,

I also I'm planing to use the Futaba S3305 High-Torque Standard Servo w/Metal Gears , are they any good? bare in mind that I do some 3d (hovering, knife edge, spins, inverted, etc..)

Kindly I need your help to make my desicion.

Thanks.