So does the BUTT Dyno agree with the improvements? Any DELTA with gas millage? Cost per Smile factor?

Haven't been on the Dyno with the X5. On my 5-series that had a signature one package, the Dyno results were very similar with what Dinan was reporting (with in +/- 1).

So, with software and CAI, I would speculate that you would see an improvement of probably around 20HP and 20ft-lb. The TB reports that you will see a +8 gain in both areas.

With just software and CAI you probably won't notice much of a DELTA difference in gas mileage.

With a TB you are allowing more air, the computer/software will adjust the fuel mappings to adjust for the additional fuel. Thus you get more power by using a little more fuel. In regards to me, if I do casual driving I do not notice a large DELTA.

Spirited driving you will notice a difference DELTA but its not THAT bad. To me, if you have a V8 and are doing engine modifications than miles per gallon should not even be considered a factor.

Cost per Smile factor for me? Well worth it and I would gladly spend it again!