I'm looking for 10 minute run times, so super high capacity isn't really that necessary and I figure 4600mah is enough even if drawing more current for taller gearing.
Edit: and the bluegroove motor mount is good piece of metal and it held up to a novak 6.5 for racing without ruining any pinions.
Like I said, I have an RCU mount, but I expect it would cost me more for the extra parts to use it. If chassis flex becomes a problem I'll switch, but I have to have a power plant and battery first