Time to work on getting the left motor to fit in its battery box for droid #2.
After needlessly cutting a corner in the hopes that would help, I started cutting through the solid... I don't know what this stuff is, but it puts up a fight.
Hack, hack, hack.
Phew! Done, after about 20-30 minutes of hacking (with lots of brief pauses). And it's nice to see I didn't cut into the motor internals.
I *think* this did the trick, although some of the foot shell edges may need to be bent a bit to straighten them out, and that could affect the fit.