I have an x3 for my 07 Expedition. I bought it through Mike at 5 Star Tuning. Mike made me a custom 87 economy (which I never use), 87 performance (used mostly), and a 93 Performance. Noticed a major difference in driving, alot more fun to drive, no more delay in the feel of the pedal, plus i am getting better gas mileage and i was able to change the computer to my new size tire so the speedo is on.