I have found a quick and easy way to turn the engine on and off. I use an extra channel on a 2 pos switch to control a pico switch which a lot of guys use to turn lights on and off. All you have to do is take a servo extension and cut the signal wire in the middle and strip the ends then attach the wires to the pico switch. Plug the extension into the receiver in the shift channel and plug the shift input from the MFU into the the other end of the extension.
Buy doing this you are able to connect and disconnect the signal going to the shift input allowing you to turn the engine on and off with the flip of a switch with out turning the radio off or going the the sequence of stick movements to turn it off.
The MFU is supposed to shut down when the radio is turned off but it doesn't because the receiver goes into fail safe. The only MFU input that will shut it down when unplugged is the shift input so that is why I break the shift signal.
Other than the fix I described above the spectrum works perfect with the MFU. I have tried this with the DX6I, DX7, DX8, and DX10 and they all worked the same with the MFU. So for $20 it is a simple easy fix and I like the way it works better any way especially since you don't have to turn the radio off.
Link to the Picoswitch
Travis