Sorry stupid question but I have an 06 cummins lifted 4inches with an afe air box, straight 4inch exhaust no muffler but otherwise stock. Im trying to decide if I should do the efi or the smarty. I'm worried about my stock automatic transmission so I don't want to go with more than 75 or so extra horsepower. Also I want to be able to reset my speedometer so my 33 inch tires will be set to it. Any help or comments would be appreciated thanks!