Something done for fun netted me a great computer.
There was really no problem. Just decided to buy an old 17" macbook pro and see what could be done with it. I wound up with an early 2008 from ebay - really cheap. It already had an SSD installed in place of the original HDD. I upgraded the RAM to the maximum of 6 GB and bought a 1 Tb HDD. You were the only outfit that sold an adapter for this model.
It was a big fat nothing. Followed the instructions - no problems until it came time to close the case. Adapter must be marginally bigger than original drive because corner of case would not close. Inspection indicated that there was a piece of black plastic trim covering the inside of the slot hole that was removable. I removed it and the case closed fine. I followed Apple's instructions and upgraded the operating system to Yosemite.
Well, yeh. I did this for fun and to see how difficult it is to upgrade an older computer. It was a learning experience in preparation for doing it to a later model 17". Only now, I don't need a later model. Nothing I do requires more than 6GB RAM, old thing is blazing fast, have storage to beat the band. So all I can say is - don't do this if you want a newer computer. You'll have given up every reason for getting one. And you'll love your old 2008 bomb that is no longer a boat anchor.