We've got the old shape X3, and we've got two Specialized Road bikes (About £4000 each).
We opted for the thule roof aero bars, Thule OutRide 561 (
http://www.thule.com/en/GB/Products/...le-OutRide-561) and the wheel holders, Thule Wheel Carrier 545-2 (
http://www.thule.com/en/GB/Products/...arrier-545_-_2) All you'd need is a different footpack..
I find they are really good, they hold the carbon frames dead secure meaning you can go down the motorway at 80mph+ with no vibrations or worry that they're going to fall off. Only thing I would say the bikes are a pain to get on, we have the running boards which we can stand on but I know the new X3 doesn't have them. The wheel holders are useful too, saves putting them in the boot.
We've got a rear Thule tow hitch for the back too, that'll hold 3 bikes, plus an extra one with a clip on adaptor. Yes we are a bit extreme. I like the fact it's easy to put on, and easy to get your bikes on and off. Although if someone runs in the back of you, your bike is pretty screwed, but saying that I find I use this the most.