Hi, I've brought you simple fun mod of 42050 B
42050 B is useless as A model, but good base for crazy wheeled "stick"
My MOD is = 42050B + 2x (Buggy motor+LiPo + Sbrick) + Servo motor.
I've tested stock 81 mm tumbler tyres and larger 94 mm Unimog tyres. 107 mm Xerion is bad, cause tractor thread pattern is bad for fast speeds.
Used iPhone as speed tracker. Not sure that it is 100% right, but cmparing to other models shared online, speed is 99% correct. Not a speed record, but it is not a bone chassis with motors also. I knew I can't beat speed record, so I've made another record: the fastest LEGO model with custom CHROMED parts (Chrome Block City, thanks to Aurelius)
p.s. In the background "AK-47 Kalshnikov" development and production plant. Historic building.