Hi Charles,
they would fit, but are you sure that you want to buy replica wheels in Europe? I guess you will get problems with the technical approval (MOT/ MFK).
For 8.5 235/35 R19 would be the perfect tire size
For 9.5 265/35 R19 would be the perfect tire size
I wouldn't take wider tires, because they will influence the tachimeter accuracy. Especially in Switzerland, this would be very dangerous because of the very high penalties.
Why don't you take the M437 wheels from the actual M4?
They have a comparable look but they are OEM BMW.
In Germany they are very in vogue for the Z4 at the moment:
