For ride quality, drivers often assume that softer shocks equal a better ride. Unfortunately, it isn't that easy. Cars with dampers that are too soft tend to bounce around from bumps. This is one reason why tuners recommend changing dampers at the same time as springs. When spring rate is increased, the system's frequency must be increased along with it. A stiffer damper is required to get rid of that energy. There's also the matter of lowered ride height that will put the factory damper into a range it wasn't intended to operate in-but that's a different column.
Most manufacturers won't divulge damping rates. However, they can give a good idea of what springs work well with their dampers and vice versa. The option here is to get adjustable dampers. Several manufacturers offer dampers that are adjustable in compression, rebound or both. Some even offer the facility to make adjustments for low- and high-frequency events (body movement being low frequency, bumps in road surface being high frequency). This will allow a car to be tuned according to the driver's needs.
Hopefully, this has cleared up some of the mystery underneath your car. It seems most enthusiasts focus mostly on spring rate and ride height. The thinking is: low and stiff is always better. But things are never that black and white. Damper tuning is as much art as science, so consult the professionals and believe that they're trying to give maximum performance and not just selling extra stuff.