I'm thinking about replacing my suerdrive in my 13" Mid 2011 MBP with a second HD (Already replaced the main drive with a 500GB Seagate Hybrid). I'd then just but an external super drive for this rare occassions when I need a DVD or CD accessed. Anyway, what is the largest capacity, reasonably fast HD that I could plug in that slot (probably using an OWC kit)? Anyone know of any real good deals out there? I'd like to drop in something bigger than 500GB as it will hold my iTunes movies and music.