Speed increases on a dead stick? So to get more speed out of my trainer at any time all I need to do is kill the engine? I don't think the physics of that will work out too well.

Glide ratio is large? I assume this means the plane will glide well? Most but not all qualify on this.

ALL landings can do damage if done incorrectly. Dead stick landings have the additional problem of no prop air over the elevator and perhaps insufficient elevator travel to raise the nose at flair time.