I got the super chips when I bought my 06 3500 4x4 new, I run it in tow mode all the time now. 135,000 miles, recent trip to Savana and back 1200 miles and stopping over at dads in SC I got 19.8 mpg averaging 75 mph (actual gallons into miles not the lie guage). The box on race mode is too radical, not sure how much HP it adds but it feels almost as good as my 392 SRT.