Yes, and that's the car I have JR-X Pro SE (with the bearing set and ready to add "Hydra Drive" setup).
Sadly, the Hydra Drive seemed to be the only real innovation that Losi flopped on. It worked well, but didn't do much better than the standard slipper on smooth tracks. The extra weight it brought to the car (rotational mass as well) didn't justify keeping it on the car. I didn't try it on my Pro SE, but a friend got a XX with it and used it, then later put the standard slipper on it, as it wasn't any improvement. An excessively rutt filled track would be the suitable situation for it, but that meant that the track wasn't well groomed.
As for the 5 link, if they had used a CVD approach to it, it would probably still be in use today. The only flaw was how they applied the linkage. A great idea, non-the-less.
Kyosho Golds, have 4 of them and yes, they are quite good, though the Losi's still work much better.
As for feeling like a historian, nah, you lived it.