Awesome truck, I just installed the 71cc with rear stear on mine as well. I noticed in the video that the oem shock piston holes are too small so the shocks are locking up which is why it's bouncing off the tires instead of engaging the suspension. If you drill out the shock piston holes to 3.5mm that will make the ride much better.
Love the size and looks of the rig, I would convert it to electric and rip it but the throttle will be replaced with a sound module lol. Way out of my price range for now.