Ryu: Just a suggestion, if you end up using watercooling, you probably wont be able to use that box. It looks like a tight squeeze as it is, but you will have to add tubing to connect the cooling plates. They add a bit of size to the esc.
Otherwise it looks amazing! I can wait to see this in action.
I ordered (4) 5000mah 30C 5S Zippy batteries this morning.
I was looking at the gear that Linc mentioned. After 40T the next size is 48T which is way too big. I wish we could get a pinion smaller than 15T. The speed calculator says 72.887 mph. I know that is theoretical but it still seems way fast.