After the springs you will need to let it "settle" a little it then get an alignment. Depends on how low you want to go and the stance you are looking for, but a lot of people also change the spring pads in the rear. I believe the stock ones are 13mm and you can switch them out to 5mm or other thicknesses. The spring pad is basically a shim that you can swap out. You can get them from an MB dealer for around $10. For protecting your fogs go here
http://www.lamin-x.com/ You can get clear or some people like yellow. All personal preference. There is also a vendor on here, Don Nguyen, who sells protective films and can hook you up. Welcome to MBworld.