I have a 2012 MBA Air 13 128Gb storage. I am fine with 128 storage as I mainly use a laptop for school purposes and what not. But if somewhere down the line I may need more memory... 1. Are the OWC SSD for MBA as good as the ones that Apple uses? 2. Would a external HD suffice and what are its disadvantages (besides having to carry it) since it isn't SSD? 3. Do you guys know of any good external HD for MBA? I'm looking to mainly store music, photos, etc. Also, how much Gb storage should I leave free at all times to have optimum performance? About 30Gb right? Thanks.