[Savage GT]

Yeah I know what you mean, I bought these 2 second hand from different sellers.
The Red Bull had the motor glued in, but with some sort of epoxy, not hot-glue or shoo-goo, you know something that could be removed easily !
So some time spent carefully removal of the epoxy with a dremel and craft knife so I could get it out and test (I wanted both cars to perform as close to even as possible).
After all that, both motors were spot on the same performance anyhow 

A strip down and clean , swapped guides for pro-race items I had in one of my box of spares. 
Then re-assembled, wheel moulding nibs removed, lubed, oiled the tyres, and now a nice evenly matched pair to added to the collection