I was told by Apple, over the telephone, that (1) if you get Apple, or an authorised Apple Repair Centre, to install the SSD for you, then it does not void the overall warranty. In such a case - where such an authorised repair person did the installation, the Mac is covered by the Applecare, but the 3rd party SSD is not. However, if the SSD is installed by a non-Apple, unauthorised repair person, then the Applecare warranty is voided. To verify this, you might telephone Apple yourself to confirm that.