Hi, I have a mid 2011 27" i7 iMac which I love but thinking of performing some upgrades to. I'm thinking of grabbing an extra 8Gb ram which which max me out at 16Gb and getting a Crucial M550 SSD (256Gb or 512Gb, undecided) to replace the internal drive. All my data is stored on an external 3Tb drive so the SSd would only be for OS and applications mainly. I would like to install the SSD internally (I have watched SSD into iMac upgrade videos so I know how to do it and feel reasonably confident). My question is, if I bought the ram and the SSD. The ram is a nice easy upgrade but could I use the SSD externally connected by USB to the machine temporarily to get the OS reinstalled and apps and then move it internally at a later date? Is this possible or not?