I received some new spare parts : fork Echo SL, freewheel 108 pts, chinese shimano crank. I am waiting for my stem/bar and the trashzen's book
I put the old fork on a scale and, wow, 1450g so I just saved something like 700g. That's massive and I can definitely feel the difference riding it. The bike feels lighter. It's less stiff, so I am really comfortable on. My arms are less stressed doing back hops, I can longer ride my bike, etc..I am already seeing technical improvements (hop to rear on small rocks and transition). On the other hand, with the new freewheel, It's better, but It's not night and day.
I am now practicing my static hops (I can already pass sidewalk steps but not much higher).