It is built in BMW's North American plant in Spartanburg, South Carolina alongside the BMW X5 whose platform it shares. It is dubbed a "Sports Activity Coupé (SAC)" by BMW, and while slightly longer and wider than the X5, it is significantly lower and seats only four people. The concept model debuted at the 2007 Frankfurt Auto Show. The production X6 officially debuted at the 2008 North American International Auto Show in Detroit and Montreal International Auto Show, respectively. A hybrid version, the BMW Concept X6 ActiveHybrid, which will be the first such vehicle from BMW, was also announced. Later, in April 2009, the sporty X6 M version was announced, with a 555 hp 4.4-liter turbocharged V8.