1- Non-M3. I can say from experience that the stock end links work with the M3 bar. Can't say the same for the opposite.
2-
plenty of other vids out there too
3- Don't have adjustable links, but when I was researching them I saw many report of Whiteline's offering falling apart.
Couple other notes cause I just installed this bar on my car - make sure you get the E93-specific bushings (31352283967 and 31352283968). When you go to install them apply just a smidge (these bushings aren't supposed to be lubed so emphases on a smidge so it dries out quickly) of dish soap to make your life a whole a lot easier. Beating the hell out of the things with a hammer wouldn't even get them on without soap while I could press them on by hand with a drop of Dawn.