ORIGINAL: SmOkEeJay
Lipo will not cause the motor to burn out any quicker than Nimh. Nimh will be hot after you run it, Lipo will not. Nimh is a dying technology in RC for a reason.
if the RC is poorly geared yes it could actually. There was one RC (I forgot which) that if you used anything over the 1800mah nicd the motor, and ESC would fry. The company used the 1800 to limit the RC's up time so it had time to cool off. Yes crappy but some of the 3rd rate no-name companies pull that.
I never heard of the ECX's(or any big brand for that matter) suffering from that issue though