I ordered a 3mm thread forming tap to make it easier to install the stainless steel machine screws from RCScrewz.
If you use this method, lightly grease the tap. For reasons you'll see in a bit...
Diff installed with rubber shielded bearings from Fast Eddie's.
Alloy gears begone! Tamiya Touring & Rally car gears in place. You can also see the GPM aluminum driveshaft cup behind the spur gear.
Top cover bolted down. That lower right screw doesn't look stainless steel does it??
Remember what I said about greasing the tap? I forgot until it generated enough heat to pull the threads out when I started to remove it. Fortunately, I found a suitable replacement screw to through-bolt the hole with a locknut. Other builds of this chassis and it's siblings say this is worth doing anyways, to help prevent the cover from lifting under power. More on the way when I can get some time!