I'm considering building an external (portable) HD for imaging using a SATA III enclosure with a USB 3.0 port. They are around $25 at newegg. I'd also purchase a 60GB SSD. Since this wouldn't be part of my Windows 7 system I'm assuming there'd be no TRIM function. I've never imaged incrementally but could of course. However, if I deleted an image and made a new one weekly, what impact would it have on the SSD? Is there a method to utilize TRIM externally? Thank you!