Well, I did a little searching, and according to ZipZoomFly, the only differences I can find are these:

- The 80GN uses an FDB (Fluid Dynamic Bearing) motor, and so should be quieter than the 4K80.
- The 4K80 has a higher operational shock rating - 250Gs/2ms vs. the 200Gs/2ms of the 80GN.

I personally transport my empeg in a nice solid Pelican 1400. If I were going to upgrade, and these were my choices, I'd go with the 80GN.