Soldered the newly arrived ESC with my new not-so-shiny soldering station and the car is kinda ready to go... class-spec tires aren't here yet but not enough vintage cars in saturday's race day anyway. Oh well, no racing yet therefore. But also tested the diff now and it definitely leaks a lot. Another rebuild needed. Oddly I noticed there's a sort of big thin O-loop like seal or something leftover after the build. I wonder if it is supposed to be in the diff even though the diff build instructions make no mention of it?