-The incredibly stupid tire implementation
If you are worried about handling, the i3s is sooo much better than the standard i3.
BMW changed a lot of parts, even the steering rack. The car is lower and wider than the standard i3. Not by a lot but it made all the difference.
i3S is 175/55 R20 in the front and 195/50 R20 in the back. That may seem narrow, but the contact patch is a decent size, especially compared to the 155 front 175 rear regular i3.
They are a bit expensive, especially the rears.
Buying wheels and spacers just to save £60 every 3 years? Meh.