For example, will a HDD mobile-rack (like the Syba SY-MRA55006) with SATA3 connectors work in a SATA2 PC (like the Dell OptiPlex 755)? For the SSD that this mobile-rack uses, does it have to be SATA3 or SATA2? I keep getting conflicting info on whether or not SATA3 is backwards-compatible with SATA2...hoping for a definite answer here, as I really want to upgrade to this mobile-rack (and my first SSD), but paranoid about wasting money on incompatible parts. Thanks.