Last major difference I found the hard way. The right side rear most cylinder (#4) has the studs tapped in the opposite locations. You will need to remove the studs from your 650/750 heads and then drill and tap holes for them in the X5 pattern. This is not a big issue as all the other cylinders are in the same place.

This engine is now in and running well in my X5!!

I will post pictures whenever I figure out how to resize them from my iPhone. The site currently says they are too large to post.