2006 GMC Dmax/Ally CCSB 2500HD, MBRP 4" turbo back exhaust, EGR blocked, EFI Live 60 RWHP tow tune by Nick @ duramaxtuner.com, Transgo Jr., 33x12.5x18 Toyo MT's, pulling 2009 Sundance 3300BHS. I don't know the weight yet, took 1 trip towing at 70-80mph I averaged 14.3. Empty I get 18, 20 with...