There are two tunes in the predator one is for performance and the other is for 87 octane.. I run the the performance tune and see at least 2mpg more overall and as for the seat of the pants feel it is a serious wake up.. My truck runs like a scalded cat.. feels faster than anything this big should be..Did you notice the power gain? What octain you running?
The vehicle's max speed is there for a reason. After you pass that mark, parts begin to wear out (transmission, differentials, etc).I use a Predator also. Performance tune is AWESOME!! I picked up some mpg and it now runs like a raped ape. It also allows you to increase the vehicles max speed if you like to go fast. It lets you adjust the speedo for bigger wheels/tires also. Very easy to use and you can download tune mods from your computer. Just make sure you order the cable to hook up to the computer, it doesn't come with it. Well worth the money.