If they come in metric, it should fit the Progress bar without any modification. The Progress bar was made to fit 12mm bolts (at least mine was).
They're dirt cheap, that's for sure. I like their stab at heim joints (rod ends) saying they'll become noisy.

Of course they will over time, but so will theirs. My rod end end links haven't become noisy yet.
I wonder if they notch the spacer between the ball joint and the mounting surface. I would hope so since that's the only thing I can see that would keep the ball joint from rotating while you torque the nut (unless they use an inset hex key like the stock end links). EDIT: The picture on the main page looks different than the pictures in their eBay store. The pictures on the main page show a hex on the stud, so that would certainly work.
I would also wonder if the metal rod between the ball joints is robust enough for a very stiff sway bar.
I remember seeing this product in Grassroots Motorsports for a few months though. Looks interesting for sure.