Something like double the width and 5-10x horsepower.
Also can't quite remember but there was something that made Twizy don't qualify as anything. Nissan ran a car sharing "experiment" using Twizy but exemptions had to be made to get plates.
This is in fact a kei car (or a mini car, AFAICT that category doesn't exist yet) if you decide to register it in Japan.
Kei car means: 660 cc engine or less (most likely moot if it's an EV), length 3.4 m or less, width 1.48 m or less, up to 4 passengers, up to 350 kg carrying capacity.
This article shows someone who has one, and note that the license plate is yellow, which means kei car.
Finally found a source! Nissan NMC product page states as below. I still can't remember why it can't be Kei registered but the consensus is it doesn't belong to any class and can't be registered outside of some special terms. That car in that article is also Nissan badged so must be under the same waiver.
> Others: Release schedule and price, as well as vehicle class, license and taxes to be applied remain undecided.
> Q:Where can I buy the vehicle?
> A:The vehicle is not on sale for now. Since the current Road Trucking Vehicle Law bans this vehicle from running on public roads, its test runs in Japan are being conducted with the special permission from MLIT under the scheme of allowing experiments of ultra-compact mobility. Whether the vehicle will be released for sale or not is still unknown.
> Q: The vehicle is said not to be allowed to run on a public road because it's over the spec of the already-defined motorized two-wheeled vehicle therefore no existing vehicle category to apply. What exactly is over the spec?
> A:Under the Road Traffic Act, vehicles that are categorized as the Class-1 Motorized Four-wheeled Bicycle are stipulated to have the rated output of "0.6kW or less" and to be a single-seater. This model’s rated output is 8kW and two-seater (front-back).
Also can't quite remember but there was something that made Twizy don't qualify as anything. Nissan ran a car sharing "experiment" using Twizy but exemptions had to be made to get plates.