Yes you can do it. Just need a hub centric cone like iqlima said. Anyway, here is what your car will look like (got these pics from Euromotor sports site).
Ori e39 M5 wheels are 18 inchers.Last I chk'd they cost rm3k each sold at auto bav glenmarie.Yes these can fit the e34 but must be used with the hub centric rings.
I have the 17 inch replicas fitted on mine.Needless to say,the finish is not as good as the ori's.Replicas can be had for rm3k or less.