[turbo6bar]

Well, I could borrow a broach, but if it's 24" long, I have no way to press it through the aluminum arm.

Actually, I was brainstorming about a new way to fasten the arm to the bar. What if you drill a 1/4" hole in the arm and the round bar and use a pin to attach the two. Let me draw it up and post later. The only advantage I see to the square drive is the fact you can change to larger/smaller sway bars while using the same links and arm.
Jurgen