Just had another issue with my def system (11 lml). For me it was the poor def quality. This is the third time it would have been in the shop for emissions. You spending the $600 or so then selling it is probably a a good option if you are just ready for another truck.
Or if you like the truck, $860 will get you the h&s, egr blocker plates, and a delete pipe that uses your stock tail pipe. A few hours of work in your drive way and you will have a great truck that is more reliable, efficient, and powerful. Never have to worry about that emissions stuff again. Good & cheap option if you are not trying to push every bit of hp.
Keep us updated with what you are doing.
2011 Silverado 2500hd 6.6 Duramax
2006 Silverado 1500 5.3L