var addthis_pub="mastersaiBMW X5 M: Official Video of Prototype ModelThe M version of the X5 has been an on-off story ever since BMW introduced the first generation model of its mid-sized luxury SUV in 1999. Now, for the first time, BMW has not only publicly admitted than it's working on a X5 M variant, but the Bavarian automaker went one step further by releasing an official video of a prototype