I currently have coil overs on the rear and shocks on the front of my car. Have been considering replacing it with airbags and have a few questions. I know nothing about airbags and how they mount.

First, can I replace my current setup and bolt the airbags in the place of the coilovers and shocks, or is it more involved than that? (other than mounting the air tank and lines)

Second, As with anyting the more you pay the better system you get. What is the average cost of a good system?