Okay, at this point I just finished applying the
small motor gear and four-gear gear-down mods to ol' Herbie to make him more rock-crawler-ish.
(I used a spare MT PCB screw for the additional gear as others have done, along with a spare wheel washer.)
The instructions were very easy to follow, and I was even able to make a set of gears entirely in matching green while retaining the blue ZZ gear ratio!!
(After a dive into the parts box!!)
Wow! It's really cool!
I'm still waiting on my springs order though.
(This week some time.)