No differences there @Meller. We are on the same page. I don´t have to explain yoú why I am also striving to reduce mass of the other things hooked up to the crankshaft thus gearbox thus rear wheels.It is the total gear ratio squared, where the gear ratio also includes the ratio of the effective radius of the flywheel to the radius of the tire. One factor goes into the angular acceleration of the flywheel, and one factor goes into the torque at the axles. So this can be as much as 100 in 1st gear, and that would really affect the launch that you can get. In 2nd gear, about half as much effect, and going down from there.
Problem with first gear is that unless it is a first gear hairpin, you lose the bulk of the advantage in feel difference on take off with the clutch. Once going with the clutch fully home you indeed do have the full advantage but I mentioned féél and the short time left in first does not give much info to notice the difference. Second and third, although less pronounced in difference, give more féél.
Nevertheless, your numbers totally underline the HUGE effect.
What is crystal clear is that the rear axle is a whole lot more lively witch less rotating engine mass. Mine has lsd and it is an almost sinful joy to light up the rear. It is só connected to the loud pedal.
All in all, though it does not give you any more hp, those availeble hps have a less heavy task so have more effect.