I recently wall-mounted some older, pre-mounting bolt M22s that by drilling into them and attaching a bracket with wood screws. I don't remember the exact type of screw, but I got the fattest screw with the deepest treads that would easily clear the holes made for them in the brackets -- I didn't want there to be any chance of the screws stripping the MDF material.
As long as the screws fit tightly into the holes you pre-drill for them, then the integrity of the cabinet will be maintained and the screws will not affect the sound.
