If you were to re-create the GTA server, firstly I wouldn't be happy with you using my map (nothing personal, I just would rather the map goes with a killer mod) Creating the map took in total no more than two weeks, but I didn't have a job at the time so I worked on it 24/7 with a skilled team.
You'd also have to have a pretty good mod for it to work. It took a long long time for the GTA mod to be developed and manipulated so the gameplay was smooth.
And lastly, of course you'd have to compete with the standard of GTA servers that I set.
I'm currently in pre-production of a server which is of a completely new genre, GTA itself was pretty unique, but this is something else. It will be similar to a city RPG and GTA, but at the same time it'll be completely different. You may sign up and help if you wish, PM me if you want to know more.
