Teonek,
Didn't you have any problems with homologation of this tyres in Poland? Perhaps you know that in EU all Muranos are on Dunlop Grandtrek 225/65R18 allseason tyres (made only for Murano).
I have on mine 255/50R19 and I passed because I got the car with German national homologation (TUV). But because there is quite some snow here in Slovenia every winter I'm looking for something for the next winter and they should be normal dimensions and specially for winter.
I think your choice is a good one! Safe driving!!!