the G and S use the same insides, but different cranks, the G has a lighter Case,

how about looking into a 91 Heli Engine, they should turn more pitch than a 91 Plane Engine,,

or you could buy a Towers or Jet Muffler for your K&B to increase power,

or you could buy an OS 70 Heli Engine,,

or you could buy a 91 Heli Engine and a Tuned Pipe,,

or you could buy a K&B 100

or an OS 75AX,

or two OS Hyper 50 Heli Engines,

or raise you Nitro percentage