I have a 2010 Dodge Journey FWD R/T with a K&N Typhoon cold air intake filter kit 69-2543TTK and just added an HyperTech Max Energy Performance Tuner. Together I am getting roughly +19 HP and +26 Torque. It breaks out to +12.31 HP/ +11 Torque from the CAI and +7 HP/ +15 Torque from the HyperTech Tuner. Additionally, the tuner allows you to adjust the rev limiter by +/- 100rpms to a max of +/- 500rpms, change axle ratios and top speed based on tire rating. You can hear and feel the power in these additions. As for gas mileage I average 20.5 mpg with mix city and highway driving (385 miles per fill up) and 23/24mpg with highway driving (420 miles per fill up).