I would stay as far away from a wash sponge as possible unless you are just going to use it on your wheels. A quality mit and drying towel will save you a ton of time buffing out swirls from poor quality products. I have gone through a couple mits and microfiber cloths. My favorite products would be the Ulti-mit and famous waffle weave drying towel.
Mit
http://www.detailedimage.com/wax.php...Ulti-Mit-P121/
Drying Towel
http://www.detailedimage.com/wax.php...ng-Towel-P100/
They are a couple bucks more than store bought stuff, but are much better in terms of clearcoat safe. Plus you save on tax and get 10% with the 10off350z coupon code. Check out Poorboys Super Slick car wash or Chemical Guys Citrus car wash, which is biodegradeable and can be used as a car wash in its diluted form or to strip away old wax and polish in concentrated form.