My 2004 X3 with sport features was known as a "SPORT PACK" and had no markings in or outside to indicate it's class. However, my 2007 X3 (also with the sport features) is marked and registerred as an "M-SPORT" and fetaures "M" markings inside the car (steering wheel, door sills, etc.) and special features outside (wheels, bodywork) - But no "M" badge at the back.
On this side of the globe you can have the "M" badge put on at the back on any model, but I think it is retarded to do this becaus it woun't be a beemer from the "M" stall! - (no offence).
F30 328i Modern Line
E83 X3 2.0d
Retired: '07 X3 3.0d M-Sport - '04 X3 2.5i Sportpack - '99 328i E46 - '93 325i E36