Made in China

Up to this point I am quite satisfied with how it has handled the load of my spare tire. I would guess it has seen a little over 1000 km of choppy trail with the spare mounted (I typically leave the spare at a base camp when going offroad since we go as a group). Based on speed and corrugation, the trails going back to camp would probably be the worst part in my case. So far I haven't seen any sign of the mount developing any play. If I had a second Jimny, I wouldn't hesitate buying another.

I have seriously considered mounting a (or possibly 2) fuel tanks in place of the spare and relocating the spare to my roof rack. Again, neither would be mounted when I'm on the trails. At this point, I wouldn't worry about doing that, even assuming a heavier but reasonable weight.

As for your other questions, aside from the initial suspension squat that mounting the bumper created, I have seen no additional settling of the vehicle. Neither have I seen any effect on gas mileage. As I waited until the vehicle warranty expired before going offroad, I can't answer whether there is any difference in handling but there was no noticeable difference onroad.