Hello there! I will be buying a pro soon to replace an old MacBook, but which model should I get? My choices are the base model and a crucial ram upgrade to 8gb, or the top 13" model which would make me poor for a few months. This computer has to get me 6 years through University, I will be running photoshop and auto cad and maybe if worst comes to worst windows 7 in a few years. So should I get the much cheaper or the more powerful Pro?