I found the SC to be more powerful underfoot, more akin to a real race ski, but not quite as demanding as the WC SL, and would turn at a slower speed (the SL doesn't really want to turn until you hit 30mph, at least it is hard to get flex out of it under that speed). The SC is probably the strongest "detuned' race ski on the market. The Supershape is more of a freeski, IMO, like an all-mountain carver. It doesn't have the lateral stiffness needed in the course. The Speedwave 14 is likely more competent in the course as well, as it is feels more laterally stiff than the Supershape.
Are you looking for a race ski that can be freeskied or are you looking to race your Supershapes? I would get a dedicated race ski, since you already own the Supershape.