I managed to make sweet fx to work by removing the next files from the game directory: D3DCompiler_42.dll , D3DX9_42.dll , d3dx10_42.dll , d3dx11_42.dll, but before copy the files sweet fx you must rename the folowing files from sweet fx : d3d9.dll to d3dx9.dll and d3d9.fx to d3dx9.fx and then copy paste in game directory and you are done ,the game looks amazing . By the way this is the link for the sweet FX i am using:
http://goo.gl/MpUAq