Hi, I bought a Suzuki Samurai back in January so far Ive fixed it up quite a bit, fixed all the rust (tared then bed lined the rear, bondoed the outside areas) Painting it is next, I've also dropped a few hundred on small things it needed. This is my daily driver and its stock, engine wise. What do I need to do in order to make it do 80 mph on the interstate without changing the gearing? 60 mph isnt cutting it and it kills my mpg. Please keep in mind this is a daily driver, would a venturi tube improve speed? I'm kind of worried that for this extra 15-20 mph increase in speed will cost me more then I want to spend, is their any cheap mods out there? Thank you EDIT: the tires are 235's