A pic would help although plastic is very difficult to deal with. If the PlastX doesn't work (I've never used it), I would be inclined to leave it. I think you will discolour it if you try to buff it. Again, a pic would help.
Ok, I just found the pics. Gotta say, I like the Edge better for a first impression. I don't like the wheels but I LOVE the roof design. Looking forward to seeing inside shots.
Be VERY careful with that on the plastic chrome as it scratches more easily than regular chrome. Collinite metal wax does a great job of cleaning and protecting them and is gentle.
Hit the last 2 digits of the door keypad simultaneously and it will lock. Either unlock it by touching the inside of the door handle, use the remote or the keypad.