I'm running Kennedy's economy tune right now. This past week I took a long trip, and averaged 20 mpg with expressway 70-75mph and some city driving. I am also running 265-75-16 tires. Speedo is correct, too.
On the expressway, at 70 mph EGT is 600-650 degrees (pre-turbo) and boost is about 3.5 to 4 lbs (on flat roads with light head winds). At 55-60 mph EGT is 550-600 and boost is less than 2 lbs.
2016 GMC SLT 2500 CC 4x4 Duramax All Terrain 59K
1995 GMC 2500 EC 4x4 6.5TD,236K,Custom Tuning,HX40W-II turbo,Amsoil Bypass Filter,KD Exhaust,FSD Cooler,KD Headlight booster,Hi-cap Cooling
TDP member #14