The OEM roof racks that you can get from car manufacturers tend to be made by Yakima or Thule. I know the rack I can get from Mazda for my Mazdaspeed is made by Thule.
Typically it's cheaper to get one aftermarket, unless you get them to throw it on real cheap when buying a car. The basic setup from Mazda (crossbars, control towers, and landing pads) was about $400. I did an entire system for 2 bikes (the above plus 2 bike carriers, and locks all around) for under $300.
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