Any auto wash using brushes is going to scratch/the worst is the soap brush wand at the corner car wash. Take a look at the other cars there and it speaks for itself.

www.detailersparadise.com has clay and lubricant, cut, polish, S21 Carnauba and the s21 polymer that lasts out to 6 months depending on how often you wash and how aggressive a detergent you use. WET WET WET. Also, they have towels, Leatherique etc. and at a fair price. Something you don't always find shopping for your BMW.