You can get a wheelchair in if you fold the rear seats, I know because I have done it, and the back windows are fixed.
I’m now up to about 300 miles with mine and so far I have spent £2.40 on electricity, which must be about 700 mpg equivalent in cost terms vs petrol.
That admittedly does include some free charging but it is out there. One car park in my town has free fast charging whilst parked, and from 8pm onwards no parking charges so that’ll come in useful for a free top up at some point.
If anyone has any questions, about the i3 / i3S or electric cars in general then fire away.