BEFORE was a 2006 S convertible with no suspension mods, other than an H-sport 19mm rear sway bar (put on by Way at MOTD) set at the middle holes and Mini Madness polyurethane front control arm bushings. I thought everything seemed right, nicely balanced.

Recently, I replaced the struts with Koni FSDs. At the same time, I replaced the front swaybar bushings and the rear strut upper bushings with Powerflex polyurethane, and the front upper strut mount plates with Vorschlags. The front camber is -1d40'; toe is .05'. I have been driving it this way for about 2 months.

It is all much stiffer, to the point where it sometimes seems like something else is clunking, but the ball joints were pronounced OK. Also, I get the feeling I should stiffen up the rear swaybar a little – does this seem like a reasonable thing, given the latest changes?

 

No. If you have more front camber, you won't need more rear bar. What is your rear alignment?

 

Rear camber: -1d43'
Rear toe: left 0d33', right 0d19'

 

You could be getting some noise from the front Vorschlag adjustable camber plates. You have removed the bearing mounted in rubber which would reduce some of the road noise. You now have a metal to metal pillow ball which can create some noise. I usually recommend using the I.E. fixed plates up front for a street car for that reason because they are still mounted in a more substantial rubber encased bearing from BMW. Also putting the poly bushing on the rear shocks mounts has had a lot of debate. A lot of knowledgeable people here believe that the rear shocks need movement in that area and poly bushings take it away. I agree with the above statement that if you have added more negative camber up front you do not need to increase the rear bar stiffness.
Another area you may check is the install of the front struts. Be sure to check the torque of the strut mounts to the Vorschlags. Also check the torque of your front endlinks to the swaybar and struts. Either of those areas could create noise.
With the addition of FSD's I would have expected you to feel a softer ride and not the other way around.
Steve

 

Thanks, all. I feel much better informed now.