I have no first hand experience with this product, but here's the Spec Sheet from the mfr's webpage...
It says "hot-swappable SATAI/II" connections so it sounds like you can plug in a bare "internal" drive. No cables necessary. "Hot-swap" means there's a bay or a 'dock' that the internal drive can be slid into.
Most hard-drives you can buy now will be SATA II or SATA III, which are all backwards compatible. If you can find a cheaper SATA-II drive, there's no reason to spend a dime more for a SATA-III version just because it's newer.
I'd ask AIOS this question, plus a couple of others...
For several years, there is a class of hard-drives called "Green" or power-savers, or sometimes the label is "IntelliPower", meaning the drives can initiate a Sleep Mode, consuming little power when the drive hasn't received Access Requests (Reads, Writes) after X minutes - 1? 2? 5? 10-20-30 - whatever.
If the AIOS doesn't support "green or IntelliPower services", then it might believe "Uh oh, the hard drive has died! It's lost power!!" It may not realize this is a Sleep Mode and all AIOS has to do is send a "Now I Need The Hard-Drive" command for it to wake up and function properly. AIOS might shut down thinking the drive's dead and no need to stay operational.
You might also ask about 5900rpm drives vs. 7200's, because I'm wondering if Heat is an issue - the 5900s will run a bit cooler, and for bare-fingers to touch a long-used 7200rpm drive might yield a VERY hot surprise. "YIKES!" followed by a quick drop on the floor, in other words. Dribbling of hard-drives is seldom recommended.
The 5900s can be pretty warm, too, but AIOS might have recommendations about one speed vs another due to heat, cautious handling and power-savings Sleep Modes.