15x5.5, ET45, 4x100, 12 lbs. Mini Cooper Wheels - $200
I bought these for my E21 but decided I don't want to run 30mm spacers to make them work. R81 7-hole (aka Imola) ET45 12.0lb (5.45kg). They have some mild curb rash that could be worked out with some 200 grit and some hand sanding.
This is the lightest wheel BMW makes (has made for them, they are Italian). They are strong, they are light. Here in this thread, they are cheap.