I'm looking to get a new iMac, but would like to use the SATA SSD from my old MacBook in an external enclosure to use as a boot drive (and maybe even make it part of a Fusion drive coupled with the internal hard drive). Anyone have a suggestion for whether to go USB 3.0 or Thunderbolt with the enclosure? USB would definitely be much cheaper, but I've heard about issues with CPU overhead using a USB enclosure in such situations; Thunderbolt is faster (and wouldn't impact CPU usage?) but the cheapest enclosure I've found that you can add your own bare drive is this one, still way pricier than USB. Thoughts?