can't be a problem.. It's not a Miata, it's a BMW. They are made to handle the cold.
I'd look for a hardtop though.
2000 Audi A8 SWB Silver/Black
1992 BMW 525iT/5 White/Blue [MPars, HIDs, cargo net]
1989 525i [scrapped]
1995 BMW 318i DASC [sold]