I found the attached brochure for the E53 4.8is. It looks like the Style 74 wheel was in fact an accessory for this model, and therefore these wheels must clear the larger 4.8is brake rotor. Based on this, you should be fine with the E70 4.8i.
2007 X5 4.8i (Performance Center Delivery, Feb 2007)
Monaco Blue/Tobacco/Bamboo, Sport w/ 20" wheels, Running Boards, Premium, Technology, Cold Weather, Heated Rear Seats, Premium Sound, Comfort Seats, Comfort Access, Sirius
2008 M5 SMG (Feb 2008)
Space Gray/Black, Comfort Access, Premium Sound, HUD, Heated Rear Seats, Heated Steering Wheel, Multi-Function Seats, Power rear sunshade, Ipod and USB Adapter, Sirius