Gf performance chip

[KNMIB]

Has anyone installed a GForce performance chip for better mileage?

[JamieGeek]

I haven't done the GForce, but on my previous V-10 (in an F-350) I had a custom performance tune from 5-Star tuning:
RV Tuners Archives - 5 Star Tuning
It made a huge difference with the "seat of the pants" feel, removed the 95 mph governor, and added a mpg to boot! (I could spin the rear wheels with the 5er on!)
I kept the programmer so that I could eventually order a tune for our RV.

Disclosure: I have no affiliation with 5-Star, just a happy customer.