As far as the roof rack, I always just wanted to remove the rub strips that are between the roof bars. It has been discussed here and they are on with doublestick tape or adhesive and will come off. I was concerned that I would mess up the paint taking them off, so I haven't done it. The roof bars themselves are easy to remove but the headliner has to be removed first.
My tailgate latch is broken too. I can't believe they had that flimsy cast zinc part for the interior rear hatch release. I even bought one off eBay Germany and the first time I tried it, it broke. I looked on the EPC and it shows a later part number. Maybe they fixed the problem.
Mercedes does not have the RealOEM that BMW has. They have the EPC (Electronic Parts Catalog). This is a link to the Russian MB site that has the EPC for our cars online.
http://www.detali.ru/cat/oem_mb0.asp?TP=1