Most of the time the airframe weight is a factor when choosing an engine.
By chance manufacturers improve their building technique, and when it's time to decide about which engine ... you have choice now.
I have been using all majors brands, and despite the weight, my favorite is the OS BELT DRIVE.
The new version I installed in a ZEBEC is the same as the first version, with a slightly increased belt size from 9 to 11 mm.

Regarding the weights, the best is to put the engine on a scale and to read …………
Most of the pics are by swk550 .... thanks