I did send my device (X) for repair under official guarantee, it came back fixed, but the back panel at some corners came loose. I've ordered 3M stickers from ebay and tried to repair it few times unsuccessfully.

Actually some time after the repair the device stopped charging. I thought the USB socket was damaged and ordered a new charging port, just to find out the port connector to the mainboard was not plugged in properly (not really impressed by the official service).

As the back panel is made of aluminum, it gets slightly distorted/twisted when it gets removed. The twist is very slight and almost impossible to make it straight. Then when you put it back after some time the pressure of the twisted corner comes slightly detached . At least, that's my experience.

I was considering buying a brand new back panel, but I could not find a complete one, i.e. back panel plus camera glass, plus some copper stickers (which form part of the main device circuitry?)