I'm considering buying a MBA to replace my 2009 MBP and found one on Amazon shipped and sold by Amazon itself for $30 off the price of the same spec model on the Apple Store. It lists the OS as 10.7 though, not 10.8. Buying via Amazon would also save me money on tax because I wouldn't have to pay any sales tax, which adds up when it costs $1,139.00. Question is: Amazon links AppleCare as an optional purchase. If I buy from there, will the computer be registered and show up in Apple's system considering I didn't buy it from them? I also didn't know retailers were able to discount Apple's products, which is why you see these buy an iPad and get a gift card offers, because Apple doesn't allow them to reduce the actual price of the product. I mainly want to know if I would encounter problems if I were to have to take the computer in to be repaired at some point. Is the old OS a problem? Is it recommended to upgrade to 10.8 and if so, how much would it cost me?