No worries, whenever you're alright to pay that's fine! No rush
Regarding the gearboxes, they might have run well this championships, but I don't know how much they've worn - they'll definitely have a reduced lifespan at 18v - wouldn't suggest going any higher though! Could always make a gearbox like mine and use those 850 Torpedo motors too if you fancied something different/more powerful - drills are fine but it's always an option!

Ah yeah, Carcinus is pretty good at sponging hits from the spinners, I think we had NST on the run in the champs - we'd have had him if he hadn't gotten my link (still want that rematch btw)
If you can maintain the angles on the front with the scoop and that on the back, you'll have a very tough machine to take on I think, might not be able to outright deflect spinners as much as say Tiny Toon or HardWired can, but having that extra bit of material for them to chew onto is always a good tactic.