1/5 Brushless 4wd Conversion

[Obeast44]

Hello guys, Ive been a member since 2008, just never posted before now. Ive been lurking for quite some time :D
Ive been a Largescale gasser guy for a few years coming from Nitro. With my work schedule and my kids I cant get away to my offroad bash sites during the week. This led me to purchase an Ofna JL10e 1/10 Onroad with a CC Mamba Maxx pro 5700KV combo on 3s, to drive during the week. After seeing the amazing power and runtimes I can get with brushless and the fact Redcat is introducing a new lighter 4wd 1/5th scale. It just seems like the perfect time to try a conversion. Here is a thread with a few pics: http://www.redcatrampageforum.com/showthread.php?t=3609

Its roughly 9kg RTR with the gas engine and all associated hardware. After getting rid of all that stuff the weight should drop down to about 6-7kg. Ive considered trying a direct to diff drive setup using a large super low KV outrunner on 12s. The buggy on 12s lipo, with the 130kv outrunner, 6.5inch tall tires, and a 3:1 differential ratio will have a top speed of 37mph@3.7volt per cell. The only thing that worries me is the rollout ratio, its 6.81. I know thats really high and it will probably cog like hell, but would the fact that itll be running at 44volts help? Bear in mind I am a complete brushless newb :)
Thanks again for any input you guys can give.