Alex C.wrote a review of Thule Doubletrack 2 Bike Hitch Carrier with STL2 Lock on September 14, 2011
Straight forward installation. Includes all hardware so you don't have to go out and buy tools to install.
Fits both bikes securely without much effort. I drive on open country roads at 70-80 mph. No problems
Only complaint is their locking system. Does take some getting use too and at times it seams as if it will not lock but keep wiggling the key and it'll lock.
Much more cost effective than a roof rack mount system if you were to start from no accessories on the car.