Well as someone who has the Scorpion here in front of me I am very surprised by the review about the tires. I got the option tires ready to put on as you know that stock tires are often hard, but they are actually really good, I used on Grass, and ashphalt without any issues at all.
My guess is the Slipper diff was locked in too hard! that's something non 2wd drivers may not be aware of! Its easy to adjust to suit the surface you are running on.
I did have the the link end come loose same as Jank but it was after a while and easy just to nip up with some thread lock. Im real happy with the car and as someone who has used and owns a Scorpion would highly recommend. For the Money I think its excellent choice.