There are a lot of options that you can replace the original stuff, the only question is it worthed? In my opinion, no, is a bit too late to create something similar to Metin. You know that if I re-write the game, that code is mine, I have the rights to use it.
Well technically I'm not selling the car, I'm selling the "ride", and in most cases, stuff in the shop doesn't exist on an official server. In any case, I don't have the rights to use the server in the first place. Like I mentioned before, my problem is with the thief part, not with the ownership. I prefer to call my self