Re: In with the new, or back to the old???
From what I know (I'm not a 6.7 owner) there were problems with the 2011 and some 2012 turbos (bad ceramic bearings), and for a couple of years there were issues with glow plugs actually impacting the pistons. As I understand it, the 2015 and up model is much improved, and even has the upgraded high pressure fuel pump, so your year should be good, so long as the DPF isn't clogged. I've heard of a few people who have had issues with that. Some delete the DEF and DPF, and add a tuner to compensate, to solve that problem, but you may not be able to depending on emissions requirements in your area. I'd recommend checking out our 6.7 forum and perhaps googling common 6.7 problems to get a better idea of what you may have to look for, but from my reading, the 2015 and up are the best versions of the engine.
2004 Excursion 6.0
New HPOP/HPO system o-rings; Updated standpipes and dummy plugs
EGR delete; Rebuilt oil cooler; CCV collection mod
VR Black Diamond head gaskets and ARP studs
Oil and coolant bypass filters; Shell EC-1 coolant
Rebuilt turbo; 250 amp alt; 6000 watts of brain scrambling
One giant 240 pound English Mastiff riding shotgun!