Answer: Do you have holes drilled in your bumper already? If so, or if you don't mind drilling your bumper, I would definitely recommend getting this plate bracket to prevent the plate from rattling against the bumper:
http://www.bimmian.com/EPH/
Other than the bracket, you should be ok with the plate and plate frame: www.bimmian.com/ELP
The plate frame will secure to the bracket and the plate will snap into the frame. This is the setup I would recommend.