I already have a GIAC flash program, just pump & stock, but I'm interested in getting the x-file program or more specifiately the FXK03 program. Who has done this & is it worth it? Also does fuel economy decrease during normal driving, or just when your on it.

 

i have apr 1+ which is the same as fx. it will add more hp and torque, i peak 23lbs and hold about 20lbs. definitely do it!