The allure of high-performance SUVs has enticed Mercedes, Ranger Rover and even Chevrolet, so how come we've never seen an M edition of the X5? Purist tradition. That may change in the next few years as BMW tests the waters in the high-output bathtub. A bevy of M models may be on the way including an X5, X3, 5-Series Estate and the Z4. Are they diluting the M badge? Nah, just following the trends. Why not have an MX5. No Mazda's got that. An XM5. Nope, BMW uses Sirius. An M5X. Oh, forget it, they'll figure it out.