The brake calipers were the culprit then.
To narrow and so the pads got stuck to often when the got dirty or a little oxidized.
We had some guys who got new ones on warranty and the never had a problem after that.
Also the gearbox seems to have got a makeover.
In my newest Twizy 02/2016 (15Tkm) you can hardly hear the gearbox while driving.
Tire noise and surrounding are louder.
There are no vibrations in neutral at 70km/h and above. Not even at 100km/h!!!
So the definitely changed something!
My 2014 Twizy started vibrating at about 60km/h and had 25Tkm down when I totaled it.