Tominator, There are not huge differences between the two. The SX-11 is 2mm wider under foot than the C-11, and the SX-11 has a metal top sheet compared to Texalium 100 in the C-11. Also, the SX-11 uses the new RaceChassis, and the C-11 has the B4Chassis. The C-11 skis really nicely. Carves well, is nimble, handles speed. It is easier than the SX-11. The SX-11 carves well too, is nimble too, but can take a lot more, and gives it back. If you want a high end all-mountain carver, go with the C-11. If you want a more versatile high end GS race ski go with the SX-11.
Rusty Guy, for a ski to compliment your SL-9, consider the R-10 (formerly called Ride 10.20). Since you want to venture into bumps (called moguls in Canada), I would steer you away from the R-11 (past Ride 11.20) because of the titanium power channels. The R-10 has more float than what you have, a less dramatic shape, a more all-mountain flex, and a rounded tail, all to make skiing less demanding in all-mountain conditions (helps save your energy so you can dance all night). I have been using the a 171 SL-11 quite a bit this spring, and enjoy it at smaller areas, where I want to maximize turn count. At resorts like Whistler, when skiing with others with longer and fatter skis, soft snow becomes a nervously intense work-out. I prefer the GS-11 or the SX-11 over the SL-11 as far as race type skis go. The R-11 and R-EX are my real Whistler ski, with the SugarDaddy being for new snow over 30cm deep.
I'm still undecided as to the skis which will be in my personal quiver, but tentative is like this:
The next would be in my demo fleet, and have 6-14 bindings with demo bands, and not the Centro:
These 6 models should allow me to ski anywhere anytime, with anyone, in any condition. Just have to make sure I pick the right one for that day. Its a good thing I can take all to the hill and switch if required.