06’ 9900i with a CM870 ISX tune options

[Luckyjayb]

I’m trying to find who would be able to provide the best tune for better fuel efficiency on my 06’ 9900I. It has a 565hp cm870 isx with 3.55 rears and a 13 speed manual. I’m averaging 5.4-5.5. I usually am 78k-80k at all times. I know it’s not the most aerodynamic truck but would love to have a proper tune put to and hopefully get closer to 6mpg. I’m located by Birmingham, al.