I've had my 057 for almost 3 years now and decided to do a little extra maintenance, well not much, but it turned into a major pita.
Initially I was just changing grips and cable on my xx1 gripshift. I had always had issues with shifting in a couple years, which I thought was due to a kink in the shift cable.
Upon inspection, etc, I found the internal routing tube seemed to be damaged, so I began routing a full length cable housing. It was quite a pita to get the full cable through the frame and into the hole in the frame.
Additionally, the shifter body was broken where the adjuster threads in. This piece is held on with a screw, but Sram doesn't sell it.
I ended up glueing the part together, running the cable and everything seems to shift better.
Unfortunately, that wasn't the end of my issues, in all the work I took the crank off in attempts to get batter access in the BB area (forgot it didn't give any access), well, when reinstalling the crank, the bolt snapped.. the only plus is, it didn't harm anything else and didn't get stuck, so now I need to pick up a new bolt before I can ride it again.