ASA, congrats on the gen 8. I bought a gen 7 about two months ago.The gen 8 seems to be thought out way more better. I bought a new motor right away. the gearing didn't let it go much faster. I had to modify an after market spur to get a little more speed. It also had a tipping problem. The batts. were mounted way to high. I had to modify the batteries mounting brackets.
So far the stock ESC is working with the 12 turn 550 brushed motor and I well have to test drive it tomorrow. Anyway, it looks like they figured out the battery problem but may have caused additional problems with that new axle design. Such as speed. You may end up buying some after market parts.
Why didn't they use two of the same size gears in the ends of the axle assemblies.