As Robin said. Weather, atmospheric pressure and the fact that all engines are different. A newer engine will less carbon build up on the valves also
I understand what you and RR are saying, I've been down this avenue many times, with various cars. Both cars were approx on 10k and just over a year old. But as Ive said before the Ed35 is definitely getting better results from the same level of tuning, and I like to know how.
Are there any Revo stage 2 Ed30's going to JKM in March, as that will be the real test. And REVO might have released the new software for the Ed35 by then..., which apparently will release more potential!
All I know is it makes me laugh out loud when I drive it, its just so bloody quick at stage 2.