west t, when I bought my new house out in n. orange county, CA, the tap water was hard as rocks. simple things like taking a shower and washing my car became an ordeal since the hard water spots would appear instantaneously once they dried on the shower doors and the car. installed a GE water softener from Costco and had a separate spicket just for my front hose line. Basically it's soft water coming directly from the unit when I need to wash my car. I have a separate line for my sprinkler system and hose (hard water for the grass and plants). Now whenever I wash my 02 sportx I never have any water spots and use a lot less soap in bucket. The rest of the home has soft water running through the water line. I usually add a 50 lb of salt from costco (3 bux) about once a month.
Been washing my cars with soft water for 29 years. Would not do it any other way! You still have to dry the car. A good on demand regeneration softener should set you back about $400.00-$500.00. Ease of installation depends on how good a plummer you are. It will also make your dishwasher, water heater etc. last longer.
Squan, bought the water softener from costco for about $300.00. Depending upon how you are planning to use it (strictly for washing your car, entire household, how many people in your home) will depend upon what size you decide to get. Had a friend of mine help me install it. Wasn't the easiest thing to do. Luckily had a Home depot close by to make extra trips for parts. Shop around at your local retailer ( I believe sears sells a good kenmore one with installation included).
My wife says the softener was one of the best investments that we did to the home. Clothes, dishes, cars and kids are a lot more cleaner.