Hi, I have just prchased a 13" macbook pro 2.5ghz i5 with 8GB of RAM. I want to use it to record and mix music on (And use protools). But, I'm having second thoughts. I'm thinking maybe I should return it and get the 13" macbook pro 2.9ghz i7. It sounds like a no brainer, but money is a big issue for me so I really cant decide what to do, after all, this is a serious purchase for me I have been saving up for. The truth is i dont really know how significant the difference between the two computers is. Do you guys/girls think it would be worth paying the extra $200 plus tax to upgrade? What about the 15" Macbook 2.3ghz i7?? Which one would you get (for recording/mixing and why??