On bowing issue - methinks it is related to the simple fact of the giant mirror that is attached to the inside of the back of the set, not being a perfectly straight surface.
As any thin glass plate would, it has some flex to it and thus, by pushing/lifting/tilting assorted areas of the TV enclosure we can see that a fix is possible, but it is tough
to come up with an elegant, non-warranty-voiding way of doing it.
One of my friends
followed advice posted here a while back: remove all the screws along top line of the screen and 2 upper ones on ea side. Using a thin instrument (he had one of those rounded and pretty dull kitchen knifes) gentry pry the front and back of the TV apart, going at it at the middle, top point, till you get a small gap to show (2mm or so).
Now, he used some black electrical tape, folded into 3 layers and stuck it into the gap. The goal is to provide a way for larger separation between the screen and back of the set in THE MIDDLE - that's where it bows the most. Samsung was partly right, advising to play with the screws to fix the bowing problem. The reason it never works, is that nothing compels the front (the screen) and the back to part and stay parted, when screws are adjusted for some slack.
With a piece of that tape stuck in the gap, it _will_ provide that separating force. Now put the screws back. In my friends case, all but the 2 screws atop, in the middle, were screwed in tight, the 2 atop were left with some slack. The bowing was gone.
No damage of any sort is done to the TV. No pressure of any sort is ever applied to the mirror. The piece of tape can be removed in seconds, should there be a need for a service visit, so that the whole voiding-of-wty issue is avoided. The whole procedure should take 5 mins. Of course, one needs to display some lines along the top portion of the screen during the procedure, for visual feedback.