I have a new Powerbook 12 inch, and want to customize the desktop... How stable is Shape Shifter for Mac OS X? I'm reluctant to download and tweak things on my powerbook, because I love it so much, I'm scared to download anything into the hd. Even When I downloaded Office Mac I was nervous as it was installing. Anyway, is ShapeShifter a great and stable program, and are there any other stable orograms I should downlaod for a great Mac experience?