I've got a full set of Style 17 rims off an E36. I seem to remember the rims being some magnesium alloy, but I could be wrong about that (they were my winter rims so I didn't pay too much attention). They've currently got snow tires on them - lightly used for one season. Looking for $380 obo for the whole package.
I'm located in Waterloo. Please email firstname.lastname@example.org
if you want to come by and see them.
Here's a stock photo of Style 17 rims: