[slimthelineman]

Plastic ones will give a little more traction in the rough stuff by letting the chassis flex front to back and torsionally a little. They are inbetween the turnbuckle type and cnc'd type. The turnbuckle ones will not allow much front to back flex but still allow torsional flex(twisting of the chassis) the aluminum cnc'd ones won't allow flex in any direction and are better for smoother hardpacked tracks like the ones here in socal which are indoor and clay. Hope this helps.