I'm planning to get a MacBook and would like to have 2GB of RAM. I can get a kit for $225 from OWC instead of the outrageous price from Apple. I know that I can put this in myself without voiding the warranty but I'd also like to upgrade the hard drive. A $120GB upgrade from Apple is $250 and a 120GB western digital hard drive is $160 from OWC. I know its not very difficult to put in myself but will it really void the warranty? How can Apple prove that an authorised repair shop didn't put it in?