The kinetic energy of the mass of exhaust gas carries it along the exhaust pipe, and causes a pressure build up ahead of the mass of gas and a partial vacuum behind it. This principle is used in a tuned exhaust system.
Culligan - $2352 ($2053 w/o R/O unit) Culligan Gold Series (10), Good Water Machine. If I were to look at price only, I would go with either the cheaper Ecowater system w/R/O at $2698 or the Culligan system. At almost $4k, the Kinetico system seems greatly over priced.
Culligan of Kansas City is rife with incompetence. In April 2014 my old water softener died after 15 years of faithful service. About 35 years ago I rented a Culligan water softener in Illinois and was very satisfied with them so I decided to upgrade to a Culligan water softener.