I'm afraid I can't help you with your GEM. With vintage electronics there's always the possibility of sudden unexpected failure. Plugging them into an uninterruptible power supply (UPS) and maintaining reasonable temperature and humidity helps, but the risk remains. As far as two sounds for the left hand, any brand's middle-of-the-line or top-of-the-line arranger has enough flexibility to do that with clever use of MIDI. You would have to add some outboard gear like a sound module, and possibly a hardware MIDI interface such as MIDI Solutions modules, etc. My $.02.