I opted for the factory bars, because they’re the cleanest looking of the options. Thing is they’re somewhat convex as opposed to being straight and if you were to cross-section a bar the front is higher than the back much like an aircraft wing. These two things have made the bars a real hassle for carrying a loaded down Yakima Skybox 21 or my 13’ Sit-On-Top Kayak. It’s a great looking design - very low profile and quiet - but not very functional. I still get by with my GM bars, but I have to use rubber friction pads to get a good grip with the clamps.
The smartest move is to get some legit cross bars from Thule or Yakima that will provide the most secure mounting surface. It’ll cost you more, but you’ll get to carry stuff with confidence. If you want a full length rack you might take a look at the Rhino Rack Pioneer:
http://www.rhinorack.com/en-us/prod...eer-platform/pioneer-platform-84-x-56-_ja9787
I had a full rack on a Land Rover D2 some many years back and it was awesome, noisy, and almost never used; great light mounting platform though.