Awsome video! I've seen it before...
Did You see Mark Fleury hillclimbing ?
Theese downshifts... You "just" have to learn how to step on two pedals simultaneously /right part of Your right foot accelerates while left part of Your right foot is braking/ The idea is to accelerate between shifts to aim the same crank/tranny speed -> this speeds up shifts a lot

It's not that hard, but needs A LOT of practice... I'll place some learning vids as soon as I will put my car together...
