I have a 2013 Ram 1500 Express. Vehicle is completely stock right down to the paper filter. I am looking to add a little more ummmff to my day to day commute. I'm not looking for tire shredding power or neck snapping shifts, but something that adds a little more power with refined shifting of the sluggish 6 spd and does not change my 18.1 avg mpg. Anyone use any tuners that might fit my need? Are there brands I should stay away from? Any problems you guys run into with any of these upgrades? Thanks in advance