rolex two tone submariner

[trueblackpercula]

Hi everyone i have a Rolex two tone submariner purchased in 2005 form a Rolex dealer to give a little history on it. I love my sub and after 13 years I want to change the dial to a silver serti dial. I have few questions if you can help me with.
1) with so many aftermarkets i cant tell the real ones from the fake ones what do I look for on it to tell if its a real one
2) will it fit on my watch without modifications to it as i want to keep it original with the exception of changing the dial for now.
3) does it hurt the value of the watch if i change it
4) any good sources of retailers that may have them

I really appreciate it

many thanks
michael