Love "washing" my cars. In 17 months of ownership, I have never washed my M3 with the traditional soap and water method. Have only used Griots Spray-On Car Wash along with their deep pile microfiber cloths. The finish on my car is flawless. Nice thing about the spray on, is that once you wipe it off, then give a good buff with a second dry microfiber towel, the car is cleaned, dried, and has a brilliant shine. I swear by the stuff. I even use it on my black Cayenne which is a my daily driver, and the finish is brilliant even on that vehicle. I take the Cayenne to a touchless car wash in winter when the grime gets on really thick, but then I still use the Griots to finish up.
I never imagined I would give up the traditional wash method, but I have, and I don't think I will ever go back.
Audi S6 * Audi S3 * Porsche Cayman GTS
--Former BMW M3 owner