It's not so much the lack of spring, as it's a lack of surface area. They tried to address this with the HT pads, but it still wasn't enough. On a high bite track, you can just crank it down and run. But on a loose track, where you need the slipper to work, you need the extra surface area. The SC10 4x4 is heavier than the SC10, and then they steal half of the surface area to drive the front, when the rear requires all of it to accelerate with authority.