I'm going to be replacing the rear upper and lower trailing arms on my 68 Cutlass S and was wondering which supplier is better and has a better cost.

 

If your going to replace just the bushings for a stock application, I would suggest using moog parts through your local parts house, or rockauto. That would be the most economical route.

 

I was actually thinking about replacing with either QA1 or UMI over stock.

 

I have the spohn arms, however I can't write a rave review about them, because the center adjustable rod is too short in my opinion. The ends are nice, but I didn't like the center piece.

 

As a structural engineer, I can tell you that putting the adjuster in the center is the absolute WORST possible thing you can do. That's where bending loads are greatest, so the last thing you want to do is to put an adjustment screw there that's smaller in diameter than the rest of the arm. The screw is now the most compliant part of the arm and it pretty much negates any stiffness benefit from the rest of the arm. Note that most arms or linkage rods that are weight optimized for stiffness have a WIDER center section and then narrow down at the ends where the adjuster is located.