it seemed to me that they had working prototypes with cars welded on, and then they were working on the next generation which was far from functional. It appears to me that you would have to spend a lot of time "converting" your car to use the treads. More than a couple of hours for sure.
I'm guessing that you have to disconnect the drive train of the car and attach it to the tread assembly, and there are problems there that they are currently wrestling with. its one thing to make it a permanent change, and another to make it "temporary".
The chevy they used was simply for a bit of glamour, it being an imported car and all...
Its fun looking...
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You can't teach experience.