I have never seen any aftermarket struts specified as being for convertibles either. There are aftermarket springs (H&R) specifically for verts due to weight difference, and the factory sway bars are different vs coupes. Interestingly, when I looked at H&R's product list, the convertible and coupe used the SAME spring # but the cup kits had different numbers?? Perhaps they do use different shocks?
The ZHP struts are suposed to be different from the ZSP package but people frequently use bilsteins and konis as replacements on verts with no problems. There is an H&R cup kit (springs and struts) specifically for verts, but I don't know if the struts are different or just the springs.
Since the aftermarket struts are different from any of the Factory struts, you would be changing regardless if you go aftermarket Why pay $$ for BMW struts when Bilstein or Koni would be better?
Last edited by jlgone; 11-03-2012 at 08:36 AM.