RE: Hirobo Jet ranger fuselage
The best mechanics for the Jet Ranger is the Freya Evo or Freya std. kit. An Xspec or EX will fit but will need additional lower mounting hole made for the foot print.
Hirobo has not modified the motor as far as I know. I have flown one as well and it is no powerhouse for certain. Just cannot horse it around and need to be ahead of it and gentle with desecents, etc.
Sorry have not tried to fit an Xcell gasser into the Freya Jet Ranger.
Jeff