This is fantastic, thanks for sharing. I've thought about doing something similar, but decided to focus on FDM 3D printed slot cars. If you want to do custom tires, it isn't too hard. You can 3D print a tire in PLA or whatever, and use it to made a mold with Smooth On oomoo. Then, pour the tire in that silicone mold with smooth on vytaflex. It comes in several hardnesses, the 40 is a safe start. If you do some googling on making replacement slot car tires, there is a lot out there. I just took my first crack at it, and it was surprisingly easy.