Like other automakers, GM faces challenges in todayâ??s plateaued, crossover-obsessed auto market, and rumors are circling that it will discontinue the slow-selling Buick LaCrosse and Chevrolet Impala and Sonic. Staying out of the â??car versus crossoverâ?* fray is the Chevrolet Silverado, GMâ??s best-selling model by far and wide. On the 1500, buyers can choose from