Hi All, I've got a mid 2011 MBA, 4,2, 256gb SSD and 4GB RAM. My hard drive is starting to fill up, and I'd like to find a way to have more storage on board. So my options are a bigger SSD OR some kind of SD card. Are people using SD cards to extend their computer's storage capacity and are they OK or are they too slow (EG for iTunes music and videos)? OR, would I be better off having the Apple Store install one of the new 512GB SSDs? How much would that even cost? I've seen the OWC option, but I won't want to void my warrantee, which I gather is what happens if you open up the case on these yourself. I don't want to use an external drive, as this is all about traveling light. Any suggestions would be appreciated. Thank you.