alright so i got a guy selling me a power pup for 100 bucks. i just wanted to get some peoples input of how good or bad this chip is. its not the triple dog, its just the normal power pup. hes saying he got 6mpg's better with it. i just want something reliable that will give a mpg or 2 better. also can i stack the pup with my edge EZ? also what does the power puck do. is it rail pressure, timing orr what.

thanks everybody