Take a while and look at upcoming beta 1 release gameplay! With full shooting synchronization, vehicle damage, player damage and client side code execution! More features to be announced!
MIV is multiplayer modification for GTA IV with synchronization written from scratch. It doesn't use built in multiplayer.
Gamemodes are written in C# and modifyable, it resembles same ideology as sa-mp, but with C#.
Release soon, after several bugfixes and preparations. I suppose I will release beta 1 tomorrow. If you are interested in playing in that release now, contact me and attempt to build from source.