If you do the math that gets you about 13 seconds of hovering.
For current performance motors, they each weigh between 100 and 150 pounds. It's very likely the roadster ones will weigh more.
The "gearbox" equivalent is about 200 pounds on modern teslas, and again the roadster will need a beefier one.
So literally just the essentials of motors and wheels and "gearbox" is now at a bare minimum of 600+ pounds. This isn't including the actual frame and structure itself, the battery, the wiring and electronics, and literally the entire vacuum/cold gas system.
I would like anyone to comment how the demo unit could possibly be under 500 pounds "guaranteed".