BMW model equivalent: 215
This site is one of the best for info on BMW wheels:
Felgen-Katalog - BMW-Treff - der Treffpunkt fr alle BMW-Fans und -Fahrer
It lists the original wheels as being 17.30kg each and 21"ers. These are resized, which may or may not be good for your intended use. I'd also ask about their load rating.
Offset is in the 40's, which looks to be in the range of other BMW wheels for the E53, per the site above anyways.
MD is right, you'll need hub rings to make them work on an E53.
GL