Don't do it, please. Why do you wanna take a serverfiles wich is public and start doing things on it? The serverfiles you take it might be having a lot of problems.. so you don't want this right? Look what I think you should do:
As a small advise I can tell ya to take a random serverfiles (game+mysql) remove everything inside of it, keep it clean, and I mean totally clean and then start adding things such a drops, quests, and whatever you need. It is more safer and more easy to maintain if you care about maintaining things.
And for the second part (source code), I'd strongly recommend you martysama. It is free, clean and stable. I am not a C++ professional coder or whatever kind of pseudocode is it wrote in the metin2 source code, but I can tell ya, that guy made an amazing job in that source.
This is totally my opinion, other people might have another opinion and you also probably have another one, but what I just told I think it make perfect sens.
English isn't my first language so I'm sorry for possible mistakes, hope I made my self understood.