Last month I took my rMBP (mid 2012) to a genius bar for a defective component (A). The repair was done in store, and all parts and labor were covered by Apple - even though my warranty was out. On the first iteration, I received my MBP with problem A corrected by replacing the logic board. However, I had a new problem: the keyboard lights were inoperable. I called, again, and they sent me to the store, again, to have it examined. Turns out the first technician made some kind of error when he was reconnecting things. Next day, I got my macbook back with new logic board (second one now), new keyboard(!), new trackpad(!), and 16GB RAM (!!). Upgrading the RAM in a rMBP, as I understand, is not an option - basically you're stuck with what you choose at checkout. I didn't realize the memory change until today when I noticed I was running a lot of software with no real (the usual) decrease in responsiveness (so I can't say if I got the 16 on the first or second iteration). Through error, lack of supply, or something else I got the upgrade - sweet. The keyboard lights work, the original problem A is still resolved, but now there is frequent popping noises coming from the right speaker, and there is a gradient across the trackpad. One corner sits ~2mm beneath the frame surface, another is completely level with it. I don't want to take it back (tired of taking it back!). But the popping is distracting, and I don't like the repeated contact I make with the edge of the frame. Ignoring the inconvenience of yet another visit to an Apple store, I wonder if it goes back for repair, if these 16 gigs of ram will again become 8 gigs. I could try opening it to resolve the trackpad gradient. I've found a few complaints on the web regarding the popping, but no concrete solutions. So far I've only lost time (no $$), and suffered a major workflow interruption. Any suggestions?