The M Sport and M Seats are one and the same thing. Real OEM confirms this, check the various part number for yourselves. The only difference is the Nappa Leather covering that is standard on the M's and optional on the M Sports (bottom photo above). The M sports depending on model/options are either Half Cloth/half Oregon Leather, Full Oregon Leather (top photo above), or New England Leather which I suppose is somewhere between the two. Its also the leather they use when you have the two tone seats.