Question for those with GC Rear Shock Mounts...

In the instructions that I got, there are two settings for the polyurethane bushing, "race" and "street." The question is this- what's the difference? For those who've been following my saga, I'm running revalved Bilsteins with the factory springs, the Ground Control rear shock mounts and TurnerMotorsport rear shock mount reinforcement plates. I'm not too sure which setting I'm going to set the RSM, basically because I don't know what the flipping over of the bushing does (I'm assuming it's sort-of-compliant versus stiff as hell). Thanks in advance!