It depends on the wheel construction and weight capacity which BMW doesn't release, there might be some codes stamped on the wheel indicative of their max weight limit but what I do know is the gross weight capacity of the E60 M5 is a little over 5,000lbs so they should be able to handle the curb weight of the E70 no problem but if you start loading the X5 and/or towing then that is where it gets murky.