Does anyone have any suggestions on how to improve fuel efficiency on my 1996 I30t? I am barely getting 19-20 mpg combined. I was looking into a performance chip by slrmotorsports that advertises +50hp and torque with +3-6 mpg. I am hesitant to try it because i am afraid that something like that would be harmful to my car. Does anyone know about these performance chips and if they are safe? Any other suggestions to improve my mpg's would be greatly appreciated!