I know you guys are likely tired of this topic..but it was mentioned a pack of 4 that works out cheaper per unit, how much cheaper..and will the LB7 injectors start getting cheaper? When the injectors go bad..do they commonly torch a piston when they stick open, or do they just leak?

very uncommon to burn a piston. Most common failure I see is excess return flow which leads to a majority of the problems. Can also cause misfire etc. I am not sure what they will level out at, but right now they can be had for 1000 per set of 4 and at this point, they must be ordered by VIN. I am still waiting on a set of 8...been 5 days so far. There is still the 100.00 core per unit.

Could the average backyard mechanic with good instructions change out a set?

Yes, if the average backyard mechanic knows his way around the engine bay on these trucks and is familiar with the Duramax engine and injector replacement and has all the right tools for the job.

Changing injectors is way up there on the difficulty scale. I would let someone like Eric handle it. Guys like him know these motors inside and out

The biggest fear I would have is something not getting replaced that needs to be or not torqued properly... Potential problems if not done correctly can be costly and/or time consuming to fix..