400 miles on twelve standard 12V batteries.
Humm, that is not a great deal of energy storage; I would really like to see just how they worked out that 400 mile figure because I suspect that it is very, very optimistic.
For example, one very lightweight and skilled driver, a minimum of equipment aboard the vehicle and the equipment that is used will be brand new, crusing on level ground at best range speed with no stopping and no other traffic to contend with, and very favorable meterological conditions.
In other words, under ideal conditions, the car can travel 400 miles.
But, I guess there will be a bit of a wait until all the facts come out. In the meantime, I would not worry about trading up just jet.