We talked about this a little up above but both Thule and Yakima make excellent rooftop rack systems that will work with whatever the top of your car looks like for a wide range of models. Some cars will have rails and need horizontal bars, some will have a slick roof and need a complete system. If you are starting with nothing expect about an hour of simple instructions to get a rack installed. It will be even easier if you have some kind of factory rail system.