I have a Mid-2012, 13' Macbook Pro, 2.9 GHz i7, 8GB ram,750 GB HDD. I'm contemplating upgrading to a SSD (256GB perhaps) and putting my existing HDD in an external enclosure. I realize there are numerous posts already about this topic but it seems every one points me in a different direction. From what I understand my model MBP has a SATA 6 Gbps interface. Ive looked and there aren't many options! Would a SATA l or ll or lll not be compatible? Also I've read that not all SDDs are mac friendly? And how important is this TRIM feature? Again I apologize for the redundancy but I need some clarification. Thanks!