I just had mine done, the full bulletproofing job / studs / egr delete / tuner / all the little usual weak points addressed. Approximately $5k for the cab off full job - just sayin' since the quoted prices and estimates are all over the map when you start reading about this work.
Truck was fine before the job but wanted peace of mind when we're travelling for the next couple of years with it.
Averaging 11-15mpg around town right now with DRW's and 4.88's, lots of short trips as it's filling in daily driver duty while my wife takes the car.
Personally I thought the 7.3 prices were a little silly on the used market, and I wanted a balance of older diesel / rust free / some comfort features like good AC and cruise etc..
Love how much quieter the 6.0 is, and I plan on doing some more sound insulation too.