Last Sunday I tackled this project, and while it was a pita to get to the ram everything was completed and my iMac is worker better than ever.
One thing I didn't expect was that internet recovery mode downloaded OS X Mountain Lion. I would have expected it to download the latest available OS, not what my iMac shipped with.
The only issue I need to iron out now is after restoring from my Time Machine, my iMac is not working quite right with iCloud drive. It pulls down new files and folders but does not update existing ones. Nor does it push any changes I made to files on my iMac. What is the best way to fix this?