2015 GLK350 base model add rear camera
 

I got the 2015 GLK350 base model.

Please tell me is my car pre-wired for backup camera? Can I install the backup camera? How much does the parts costs? Should I get to a mechanic to install this or at the Mercedes dealer?
I searched the computer on the steering wheel control, but does not see the listing of reverse camera.

My roof rails are black. How do I remove these roof rails?
Is remove & install these 2 roof rails simple and easy? Where can I find instructions?

Period maintenance is every 10K miles right? Should I have this maintenance done at my favorite local mechanic or at the Mercedes dealer?

Thank you.