Recently, I would like to upgrade my harddisk from the 250GB 5400 to 500GB 7200. I have looked into Seagate Momentus ST9500420AS, and I have few questions about it: 1. wondering will it fit my MBP; 2. does it have the free sensor like the Hitachi HDD which came in MBP? 3. How is the performance? Or does anyone can suggest me with a better HDD?