hey guys, i'm installing some more RAM on my new IMac and had a couple of questions. 1) Can I buy RAM anywhere online other than Apple? If so are there any good sites etc? 2) Is there any special type I have to buy? 3) They don't have to be matched pairs or anything right? 4) If I install it myself will it void my AppleCare? If it does, can I buy it elsewhere and have an Apple store install it for me? I just don't want to buy it from them due to overcharging. thanks in advance!