I've been using a product that I buy at the Los Angeles Auto Show every year (for about 10 years now). Do a Google search on "Simply Z-Best" car wax. It's a liquid wax that is truly amazing and very easy to use. 

I had not heard of this wax.  Thanks for sharing .

I have a 2011 E550 in Palladium Silver. I only use Zaino products.
The first time is a bit tedious but no more effort than any other product would
need if you're going to do it correctly - ie. wash, clay, wash then wax......

Check out their website - www.zainostore.com - Their products are the best I've found.
My M-B dealer asked what I used - that's how really good it looks.
Maintenance is a snap. Good Luck.
Regards

Les

I also have a 2011 palladium C300.  I use "Klasse All-in-one" and it's a great product.  It lasts a good six to eight months under normal conditions, and monthly bucket washing followed by a runaround with Meguiar's quick-spray wax makes the car look great every time.  Bird droppings and other insults are easily removed with water between washings if needed; I keep a water bottle and a few microfiber towels in my trunk for that purpose. My car is a year old now and looks just like it did when I bought it.  Application of Klasse A-I-O is super easy and requires only one thin coat.  Good stuff.  Find it at http://www.autogeek.net/klasalpolsea.html

Try Collinite Heavy Duty Wax. Extremely durable - Brske dust on my Chrome Rims rinses right off with

Thanxs