Welcome Scott!
You can find the official TSB info here: http://www.ecodieselram.com/forum/threads/tsb-18-078-16-engine-oil-viscosity-upgrade-and-flash-enhancements.1178/
Many posts (and opinions) on the forum about it. Read up and ask any questions you may have!
Craig, the only exhaust that works with emissions intact would be a DPF back exhaust, and those are for looks only. You won't have any sound differences.
To run a full aftermarket exhaust , and to hear a sound difference, you would have to buy "off road tuning" that disables the emissions...
That's great info @Nutt .
You should have done a write up and documented it for us :D. I have a feeling you won't be the last guy to have this problem.
Welcome!
Sorry to hear of the troubles. These trucks are no different from others, they all break. Sometimes we just get unlucky.. I wouldn't let this repair steer you away from the platform. If you like it, and still enjoy the truck just drive it and be happy.