I drove my first longer distance yesterday, 130 mi, to really get a feel for it AND Cold air intake. On 15 Ram 1500 5.7. I'm not sure if it's the programmer or intake that's giving me the extra MIDRANGE to top end power. I thought it would be "snappier" off the line. Now it's at 2200-4200 power band and it's a beast when it hits. Mileage is no difference. The Rep said 35-40 hp increase plus 15-18 with intake. That's 440-450 HP. It DEFINITELY helps. How much? Not sure yet.