From what ive experienced the lambswool sponge or mitt is one of the best,as long as everything you use on the paint work is clean and free of dirt its all left to the soap to do most of the work,a good soap will make more the difference,some car washes have spot free water and air dryers they make chamoing easier,one thing to remember monthly waxing will always keep your car looking good,its all down to maintaining the paintwork.