Originally Posted by kstephens

This. Too many variables (a slight bend in the roof, excess dust...). For the price a decent, roof rack or hitch can be installed. I have also never used a temporary rack (trunk rack or temp. roof rack) that didn't eventually leave marks on the car. It may not the first few times, but after extended use and the tendency to get careless after you are comfortable with the install, eventually there will be marks/scratches/scuffs from it.

I've still yet to find a rack that I like as much as my 1up.