Not sure if this was asked here before but I remember that changing the hard rive on a MBP (non-retina) does not void the warranty. I got a MBP 2011 model whose warranty expires this year. I had replaced its 750GB hard drive with an Intel SSD. Off late though, I have been having kernel panics related to GPU (See here). I called up AppleCare to test the waters and see if my warranty still holds up and to my surprise, they said no! I would like to dismiss this as lack of information on the AppleCare rep's part but anyone here with experience on this matter? I have since restored my MBP to its original config and as expected, things have slowed down to a crawl!