Those are in my building thread listed below (starting at post #62, at least I think that's what your refereeing to) They are Kinetico systems and are very nice but over priced. I use a model 100 to remove my hardness (65 grains hardness) And I have a Kinetico R/O system installed too. You would have to have very large RO unit if you were going to wash cars with it... Remember too that if you have hard water the softener will replace every grain of hardness with a grain of salt....
William....
I have a water softener for my house & garage, and a "Reverse Osmosis" system as well.
When the wife washes dishes, she still gets water spots -- but these water spots are not "hardness" (typically calcium carbonate in our area) but rather are "table salt" type deposits that brush off prettty easily. So, when she washes silverware or crystal or wine glasses or whatever, she gives things a fast rinse from the RO water dispenser -- then when things air dry they are spotless.
A typical residential RO system has a holding tank of about 3 gallons -- enough to supply people with drinking water. You could wash your car with soft water, and then give it a final rinse with RO water -- but you would probably need to get a unit with a much larger tank - say 10 or 15 gallons.
Some soft water companies sell systems that do not use salt - instead of ion exchange (where sodium ions are exchanged for the calcium and magnesium ions in the water) they rely on magnetism or other techniques. Personally, I do not believe they really work: see for example
http://www.chem1.com/CQ/
You can see on the left the yellowish tinge. It's about time to replace the filters. Normally I can change the left one twice before I need to replace the right one (charcoal).. Each tube holds two filters.