Those are some miraculous tubes. At a meter long, that's 6cm in diameter.
At 5076psi, I get 22,700 pounds of axial tension plus 12,000 pounds transverse tension (per inch of length). Checking a section of the pipe yields 3060 pounds axial and 6000 pounds transverse on an inch by inch element. That's 6735 pli rotated 63 degrees from the axis. Using rational factors of safety (usu ~4 for CF composites, 1.6-2.0 for isotropics), I get 1/4" wall 7075-T651 high strength aluminum or 5/32" wall carbon fiber in an optimally oriented weave - not including the matrix/weave thickness or containment (CF vessels for HCs are almost always aluminum lined, I presume H2 would be also). That's 80 cubic inches of aluminum per tube (about 16lbs total) or 10-11lbs of top-quality carbon fiber. They're out of margin for everything else in their 5KG vehicle.
I suspect that their product is paper based (i.e. the numbers work if you assume the best case for everything), but will be exceptionally difficult to make actually meet products. I expect to park a Moller air car in my driveway before they make this project work as proposed.