The "M Exclusive" fix tricks the game into using for the DLC shaders. Because the DLCs introduced new particle effects for sandstorms, the game refused to render them on Windows 7. By applying the d3d11.dll wrapper included in the M Exclusive pack, you force the game to render DLC particles via the CPU, which is slower but functional.
Would I recommend it? Only for offline testing on legacy hardware — otherwise, no. dakar desert rally 2 dlcs windows 7 fix m exclusive