That page is full of marketing baloney. However, to summarize, the developers have created a dock where your super drive goes. It does nothing, it's a piece of metal. You can pick up data doublers from eBay and many other placers for a lower cost.
No, actually, it might do something, but that something is really superflous, it might make it slightly easier to install your drive, but at a cost as per usual with Mac specific accessories that is kinda ridiculous for what it does.
The issue you are having that is specific to the 2011 MacBook Pro is with the SATA cable, and it not being designed to run at SATA3 speeds, the other issue your having is a compatibility issue for which only certain drives work.
- I run a Crucial MX100 in my 2011 MacBook pro which resolves the issue of drive compatibility.
- Data cables are hit and miss. If it doesn't work in your optical drive bay you are ***** out of luck If it doesn't work in your hard drive bay, complain until you get a new data cable.
- You are messing with a non-user serviceable device, anything you break will be charged to you at out of warranty costs.
Apple is not even
remotely interested addressing this issue, let alone solving it, so good luck. If it fails you
will be charged an out of warranty repair fee for an Apple genius to fix whatever issues you have created and nobody will save you. Where I live the out of warranty service at my local authorised repairer is a flat fee of
$70.
To repeat
Apple does not care about this issue, if you are not confident in what you are doing, or do not have the necessary Phillips and Torx drivers, do not proceed and pay an Apple specialist to fit the drive for you.
It's really quite simple, take this on authority.