Hi there, So my uMBP 17" arrived today. Bloody nice machine. Still getting used to the size coming from a uMB 13". My question is regarding the HDD. Its a 500GB 5400rpm Hitachi drive (the stock model it comes with). I have a 500GB Western Digital one I bought for my Macbook - not sure whether its faster - its a 5400rpm drive still. What are other peoples views on the Hitachi 500GB drives Apple use? If I were to buy a faster drive, and fit it myself, does that void the warranty? If so how do I upgrade the HDD? Through Apple? thanks.