"...I've heard of a few seal leaks on the FJR final drive and I think one failed from the drain plug falling out out but otherwise it's a pretty bulletproof unit"
To clarify (and support) Ray's point, I can personally attest to the accuracy of that statement. My Gen 1 bike had a pinion seal leaking after 50,00 miles, which was replaced on my shop bench in about an hour.
On my first Gen 3 bike, after I performed the 600 mile "break in" rear end fluid change, and forgot to torque the drain plug (dumb ass Pants), at the next ride, I rode the bike no less than 35 miles (and likely more) in 95 degree heat and at speeds averaging 70 mph with ZERO oil in the rear end because the drain plug fell out and struck a friend in the chest behind me. In the middle of no where, I re-filled the rear end with outboard motor oil GL-5 I grabbed at a fishing bait shop, transferred the fill plug to the drain hole, and stuck a fishing cork in the fill hole, and RODE THE BIKE HOME 60 MILES. When I drained the GL-5, although it had some metal in it, there was no noise or vibration what so ever. In caution, I replaced the pumpkin.
Now - if that doesn't speak volumes to reliability and bulletproof-ness, then nothing does....