Looks awesome squid. I hate to say it but I think you will eventually find the gearboxes failing. The weak link is not the gears but the lack of bushings that the shafts fit into. I went with the metal gears and had it grinding after a day in the rough. A lot of slop will develop between the pinion that comes out of the gearbox and the larger drive gear.
The rest of the mods look great.
Perry