My neighbor has a CR Spotless water de-ionizer that he purchased from Costco for $500. It works great - think large scale Mr. Clean Spotless Car Wash system; however, I wasn't willing to spend that much to have de-ionized water. I purchased a hi capacity WaterStick De-ionizer for $89 and it worked equally as well as the CR Spotless system. I installed it in-line to my pressure washer without any flow problems. I tested it on my XKR, which is black and the water evaporated without any spots. Initially I thought I would have to wait for Spring to use it; however, we've had extremely warm weather in Virginia and I was able to use my new gadget this weekend. I'll probably use it a lot in the spring/summer to hose off the pollen of the Range Rover, which has to live outside.