The control arm bushings come as a pair. # 31 12 9 064 875
www.eap4parts.com (my fav) has the pair for $54.95. PelicanParts has them for $69.40.
What's the M Strut Kit on understeer? I can't find it.
On my site I broke-down the suspension intall kit that's on the Understeer site. Although I added the front strut mounts to the list.
http://www.geocities.com/threeiswee/installkit.htm