I drive my coupe as normal. It won't be tucked up for winter, although I won't be taking it out if it's several below zero or snowing.....that's what that the daily driver is for....and why I bought a quattro.
Just stick -10 degrees screen wash in it and use a jet wash more often, if not sure about grip stick some all season, or winter tyres on until end of March jobs a gud en
I dont use mine from November > April
Time for the old Land Rover over the winter months
Those that do and use Waxoyl - might be better to use Lanoguard, easy to apply DIY plus not messy and degrades after 12/18 months.
Kits about £70 and would do 2 may be 3 seasons on a Z4. I do my Land Rover every year in the summer months in readyness for the winter. Does smell like lam chops for a while mind