May I ask how much were the upgraded rims - the all alloy ones without the plastic trim.
Also do you have to remove all 4 wheel nuts of the stock alloys (whilst the car is jacked up) in order to remove the plplastic trim?
Yes no problem!
They're the original Honda ones, available as optional.
As said in other replies, Honda doesn't ask you the OEM ones back so you end up having two sets - which is exactly what i needed, so I can easily and rapidly swap between winter and summer tyres.
I paid them 800 EUR (list price is 1.120EUR), which is a bit higher than a generic wheel set (you can find good commercial ones at around 600EUR) but in this way I was sure they were perfectly fitting with the car.
It's very difficult to find 16" rims with ET50 and 6.5J width (normally they're 7J and ET45).
Regarding the other question, yes you have to remove the nuts before you can take away the plastic fairing.