Bumping up an old thread, as I haven't found any close-up pics, though I did find some forum members who are using these racks on the factory crossbars.
I picked up some Thule 594 Sidearm roof racks from craigslist, hoping to use them on my current Yakima rack. Unfortunately, I don't have enough Yakima crossbar extending to the outside of the base (i.e. where the Yakima base clamps to the 4R rail) to be able to mount the Sidearm on the outside. I would have to mount the Thule racks "inboard" of the Yakima base.
If I'm doing that, I may as well reinstall the 4R factory crossbars and mount the Sidearms straight to the factory crossbars -- they'll be closer to the roof (lower) and hopefully make a little less wind noise.
I know the Yakima/Thule aftermarket rack is stronger. But is there anyone here who has been using a Sidearm rack mounted straight to the factory crossbars, and using them for awhile now? Satisfied? Dissatisfied?
FWIW, I have the SR5 model, with the thin rails and flattened-looking crossbars. (Not the Sport with the tubular rails.)