My guess is that it's not that significant of an increase in weight. They're removing everything including the axles, and putting in their own. Guestimating based on the video, I'd say each motor+axle weights similarly to a transmission, the engine is a lot smaller but add the generator, that's probably a wash. Batteries, they're planning to be small and cheap (because they have a generator), so lets guess 20kwh, so maybe 300lbs in batteries. Fuel tank stays, drive shaft is out. So, basically a total increase of one transmission (150lbs) and 300lbs worth of batteries, so 450lbs in all. Definitely heavier, but I think it's a far cry from 10x. 2x would be my guess, which seems well within the realm of reasonability