Acura was refreshingly open about the fact that its MD-X concept is the basis for the second-generation 2007 Acura MDX SUV that goes on sale this fall. More aggressive styling, a slight increase in size, and better handling are all promised for the next MDX. Despite showing us the future shape of the ute, Acura was tight-lipped about the powertrain. A safe bet would be a version of Acura???s familiar 3.5-liter V-6 with at least 270 horsepower.