Consequences of chipping a 5.9?

[Edgemann55]

Smarty Jr has been on my truck for 50K trouble free miles. Set on performance setting 3 I see about 1. 5mpg gain and the best part is the reduced egt's as I never exceed 1100 even pullin the grade to Tahoe hard from Carson City. Use to hit 1350 all the time before. Bang for the buck was a great add on to my rig.