It is street legal, Kurt drove it to mogfest last October, it is huge, it makes a mog look like tonka toy.
As for changing the tire, I have no idea how you do it. A mog tire/wheel is going on 250 pounds, this is the limit of manageable by yourself, the MAN tires must be 350-400 pounds each, ir does has a hydraulic arm that lowers the spare tire so no crane required.
The trick to mounting a 46 inch, 250 pound tire by yourself: Get the wheel in position, rotate the hub by hand so the studs align with the holes. Adjust the jack so the studs are half and inch higher than the holes in the wheel. Put your feet either side the wheel like chocks and roll it back onto your boots. The other way is you use the wrench as a lever, the handle of my 24inch wrench fits nicely between the treads of the tires so it can't slip.