Waranty and Apple Care plan after exchange of SSD?
When I purchased my early 2013 MacBook Pro with Retina Display, as well as a previous MacBook Pro seven years earlier, I specifically asked about changing the HDD and RAM in the older one and the SSD in the newer one myself and in both instances I was told that it didn't void the warranty as long as there was no evidence that the work done by myself was the direct/indirect cause of a subsequent issue.  The problem with such a response is having to prove on my part that a subsequent issue was not the direct/indirect cause of the subsequent issue if Apple challenged repairing it under warranty.  The sales person and tech at the Genius Bar both said that Apple expects that some Users would upgrade parts like HDD/SDD and or RAM where applicable and said it doesn't directly void the warranty in doing so, except with the aforementioned caveat.

So I waited until the older one was out of warranty before I upgraded both the HDD and RAM.  The newer one I maxed out at the time so I doubt I'll pull the 750 GB SSD any time soon or within the warranty period.

Good luck with Apple!