After that, I moved on to the C-pillar.
To remove the C-pillar, you need to remove the following: the rear reading light, the vent window weather stripping, the side bolster and the rear side panel.
For the rear reading light, just pry it off with a screwdriver.
Then remove the weather stripping. This can be a royal pain in the ass, but mine was coming off in one section, so I got lucky. It also helps greatly to open the vent window.
Next is the side bolster. Super. I got in a small scuffle with my passenger side one, but the driver's side was sehr, sehr easy. Anyway, there are three mounting points on this piece. The first you need to remove is the top tension spring. It took me all my might and a bit of physics to release this one. Try and wiggle it out a bit and then get behind it with your hand and pull like there is no tomorrow. The second is merely a problem of lifting it up with ease. The third should come out easy, but this is where I got into the scuffle. You should just be able to slide it towards the outside of the car, but if the leather/vinyl gets stuck on the little nub, be prepared for a party.
In this picture I have marked the mounting points in red and drew in the direction it need to move to unlatch with some ugly blue arrows. Also, I provided a close up of the side bolster "nub" in the last two parts of the picture.
Here is a view of the back. You can see the first two mounting points. The top one is the tension spring and the bottom is the hook.
Again, here are the mounting points.
Next is the side panel. This was surprisingly easy. Mine just lifted up once the weather stripping and side bolster were removed. However, on newer E36's, three clips are used at the top. Simply lift and apply pressure where the clips are.
Here are a few views of the side panel:
And a view from the back: