Thanks for your earlier post. Regarding the noisy backseats, you're correct that most of the noise comes from the upper portions of the backseat sides. Like you did, I placed some folded Kleenex tissue between the rubbing area. It muffled 70% of the noise but it didn't completely eliminate the noise. At this point, I can't really pinpoint where the other noise is coming from but I'm guessing it's coming from the plastic cover on the upper portion of the backseat side (my 323ci has this plastic cover but I'm not sure if sedans have this). As an experiment, I placed more Kleenex in every nooks and crannies but I still can't eliminate the noise.
I remember seeing someone's post about applying Vaseline. Have you tried this? I know (in my case, too) leather conditioner doesn't work because it dries out after a few days. How was your visit to dealer? Please let me know if you have found any solution. Thank you again.