Fitted the new anti-roll bar kit to my car - trying the 3mm one first. I came across a similar problem to the front alu anti-roll bar holders, in that after mounting the new rear kit, the suspension was binding
I assumed that the clamp holding the anti-roll bar was a little too tight, so I removed the paint from the anti-roll bar and polished it - no improvement
Next I check the ball joints which attach to the end of the bar itself. They also seemed to bind a little in the plastic cup, so I took them out and polished them, too until they moved freely......no improvement!!
Then I noticed that the adjusters (the items connecting the bar to the suspension arms) were touching the rear drive shaft
I loosened off the retaining screw on the ball joint and moved it along the bar a little (2mm). Now the adjusters no longer touched the drive shafts and the suspension no longer binds
Oh well, you live and learn
Here's a pic before I started polishing the roll bar