The CR has variable speed V-belt drive for both the rotor and the feederhouse. If you open the side shield on the right hand side of the combine you will see both large variable speed drives. The rear one goes to the rotor gearbox and the front one drives a jackshaft that runs across to the left side of the combine where the feederhouse hydraulic clutch is. The clutch then drives a 4 or 5 band V-belt down to the front feederhouse shaft.
You can run a 12 row head on a 940. If your looking at aftermarket chopping heads they do use more power. You would want to have the optional larger 70MM lift cylinders for the extra weight. The standard 62MM cylinders do good with a 12 row 20" head. I'm not sure how much more a 30" wide head weighs.
As far as price I only know for cetain what a guy near me paid for his. His is a CR940 2003 model with planetary final drives, RWA, long unloading auger, fancy cab, yield monitor, 300bu hopper. His was right at $220,000. He farms about 600 acres and milks cows. He said he figured he should get 15-20 years out of this one.
Based on combine class size, rated HP, graintank capacity, it would be comparable to a 9660STS or a 2388. From what I've seen in the field with the current 7.5L Genesis engine and the correct engine software it will give any 9760STS a good run for its money. with a 30 foot auger head you can get 6-6.5mph with very little shoe or rotor losses in good soybeans. In beans max power becomes the main limiting factor. Once you find the speed that is comfortable to run at in a field you can pretty well get the separator set to clean at that chaff load. In corn you never reach the max power(fuel) limit. I know that there were complaints about the shoe in 970's and 8010's in over 30% moisture corn. I can say that shelling in the high 20's% range that the 940/960 shoe does not throw corn over. I don't know of anyone around me that runs in the 30%+ moisture range so I can't say how it would do there.