6th winter here in Slovenia.. We have snow about 30 days a year so quite a bit. I use the box year round since 2006 when I bought it.
Absolutely no problems at all. All I do every year is the following.
1. Anti freeze in the wiper fluid
2. Snow tires (which are required by law) between october to march.
3. Treat the soft top with some scotchgaurd or equivelent.
No leaks.. No deteriation of anything. Easy to drive on the snow, just dont have a heavy right foot and dont accelerate into corners
All good. Cheers