Do you already have the M System II rims? The throwing star design is acutally a hubcap that bolts onto the M System rims.
If you already have the rims, lucky you. Go to
www.pacificbmw.com and they should hook you up for a decent price (BMWCCA members get extra discounts)
If you need both the rims and hubcaps, I would also go to Pacific BMW. The rims will be expensive anywhere you go. Here in Colorado, the dealership average is about $450 per rim, not including the hubcap pieces.
The ones on Ebay are replicas and of lower quality, and even sometimes a different design. Weak.
Go for the real stuff. It is reliable and high quality. You will be happy with it. Not the price though....