So, normally no worry at all ! It'll pass the expertise easily, especially in Valais. They're a lot more tolerant about car the some other states...
175/50r15 can be put on the stock wheels easily. they look a little chunky but they fit and work fine. That's the setup that came on my Copen when I bought it.
Hi ! After a long time without any news, here is the last modification : A Pioneer double din with CD player and DAB+: And it's antenna...
Other then that, I've to say that I'm veeery happy with my suspension setup and the Nankang NS2R ! Car is great on the road like that !