whats up with the price of upgrading RAM on apple's machines?! I've got a mbp with 2gb ram and am thinking about going for 4gb. on the apple site, when ordering a new mbp, it costs an extra £450, but i can buy 4gb ram from crucial.com for just over £100!??! whats the deal with this? is the RAM from crucial rubbish or is apple ripping people off?