I recently bought a '07 ZX-14 California model with 4500 miles with evaporative emissions. Is it possible to get rid of the emissions and can I do it myself? Is it even important or worth fretting about and should I just leave it alone? What is the consensus on dealing with California emissions anyway? Does it really slow things down and give you bad milage?

No, no mileage problem. Better you keep it in and have the [octane] vapor all fresh, not floating out into atmosphere. It's all hype if you think about that vapor going weak and making the gas that much weaker on a performance bike like this.