Gday all, i just have a question. My mate and i both have 180sx and both have RB20's in them. Mods wise they are very similar in that there isn't really any. But when we are travelling at similar speeds are revs are very different. E.g when im doing 100km/h my car reads out that im doing 4500rpm while my mate at the exact same speed is only doing 3500rpm and they are both in 5th gear. Could anyone tell me the possible reasons for the difference in revs and could this be a problem.