Changing an E50 system to E60 is very easy as E60 fits into the same back box as E50 and uses the same connections for *speakers and line auxiliary input. You will however need a small adaptor for the power supply, as E60 uses a slightly larger socket. You can purchase a small 2.1mm (female) to 2.5mm (male) DC power adaptor from Amazon:
Use the adaptor on the end of the E50 power cable, making it possible to plug into E60.
*Note, that the left loudspeaker termination is reversed so, you'll need swap the +/- terminations around on that channel only. See photos
E50/E100 speaker terminals.
E60 Speaker terminations