I own a 2007 335i sedan. I am considering installing the roof "base support system" (roof rack) so that I can install bike racks on them. It appears each support is attached with one bolt on the roof. Question 1: Is this something I can install, or do I need a special tool? Question 2: If I can do it, is it easy to take on and off (the base support system, not the bike racks) since I prefer the clean, no support rack look. Thanks for any help.