IMO... an exterior rack is the way to go. The interior of an X5 or X3 is not going to be ble to swallow two bikes without the rear seats down. If you ride often, you will quickly get tired of dragging the bikes in and out of your car, folding and unfolding the seats and (if mountain biking) cleaning the grime from you carpeted interior. If gas mileage and protecting you bikes from flying debris is a concern, get a rear trunk carrier. I personally use Thule 450 Crossbars with the factory rails as they are less expensive that OEM bars and are made to fit my other Thule systems for my canoe, bikes, snowboards and luggage bag. As to Thule vs Yakima... the choice is a matter of preference and often religious... SQUARE RULES... sorry, if came over me all of a sudden.