Twenty minutes after we began lapping the BeaveRun road racing course, thick, charcoal-colored skies rife with brilliant cloud-to-ground lightning and booming thunderclaps rolled in, accompanied by a torrential downpour. What good is a road test of a new SUV on a nice dry race track, anyway? Fortunately, Acura never called us in, so we raced from the MDX to a Porsche Cayenne V6 to a BMW X5 3.0i and back to the MDX in the rain, the thunder, and the lightning, and we learned that the Acura MDX is one capable foul-weather conveyance.