The 5X120 bolt diameter is common for most modern BMW's. The wheel offset is a key measurement that helps determine interchangeability between vehicles. X5's can handle a offset range generally somewhere in the range of 38-45; E46's offset ranges are usually between 35-40mm. In the overlap range of 40-45mm, you'll find the wheels that are interchangeable.

Although I haven't seen them installed in real life, I would imagine X5 wheels on an E46 would not look good. I have seen M3 EVO wheels on an X5, and that did not look good either.

Alt aka Miro makes also Hamann replica.