I don't think the link is working shogun?
I just did this yesterday and it didn't go to bad. Remove all lights, hand holds, sunroof panel, and sun shades. The door seals have to be peeled back at the top and the trim from the A,B, and C pillars all has to come off. Most of this stuff just unclips. The one thing that took me a while to figure out was how the headliner was clipped at the rear window. After some study I pulled the headliner sideways and it slide off the 3 clips that were holding it at the back. I think I could have pulled straight down but I was afraid of tearing the headliner.
Do a search on headliner and there will be a link to a company that sells them but also has a nice write up on how to remove them ... 525i w/ sunroof.
I am going to bring my headliner, sunroof panel, and rear parcel shelf panel in to be recovered today ... if I can handle the price.
hth,
Dave Menheere