I got my 2000 4.0L 5 Speed Sport back in August and have just been driving it and not worrying about gears and other mods. Now I have been looking around and am starting to get questions. I believe that it is lifted 4" with 31" tires. Eventually I want to get 33s I think it has stock gears, looked for the code earlier but it was too dirty to see and I'll check it again tomorrow. Will 4.56 gears help me on the highway with maintaining speed in 5th gear or would I still have to downshift (I think I have 3.07)? Would it hurt mpg or not change it? Right now I'm getting 10. And how much do good gears cost? Any extra help/info is greatly appreciated! Let me know if you need more info and sorry about the length.