You're in luck, EVGA has $300-$320 980 Ti's in their B-stock catalog: http://www.evga.com/Products/ProductLis ... ies+Family
CoC is very well optimized if you use the enhanced DX9 renderer (R2.5). All you will lose is volumetric fog compared to DX10.5 or DX11. CoC does remove some of the annoyances of the later renderers compared to CS and CoP like the super slow load times, but they are just not as fast and you gain precious little in functionality.
My almost 4 year old 7970 (OCed to 1150MHz) can run CoC with most everything maxed out other than a conservative grass radius and not come close to maxing out the GPU. Afterburner shows it at about 75-80% GPU usage max.