It is basically just a package containing the base game + DLCs.
No special version, the latest trainer should work just fine.
I think the problem might be that people like myself have the low violence version. And others have the uncut version which might explain why the trainer may not work. Caliber are you able to look into this problem.
[Edited by wozjtf, 7/28/2014 7:31:08 AM]