I upgraded mine o a 160gb 5400rpm. So far so good. After installing/uninstaling some apps to see which ne i prefer, i back up everything and did a clean install. Pretty straight foward i must say. Gained some decent numbers (although i dont know them im sure i did)
Plus, i have a 160gb 5400 rpm Western Digital Passport (the black one), very nice btw) that works beautifully with this SR MBP.