A few years back, Acura set out to realign its rather varied lineup towards a more common thematic focus, and the success of the effort are in clear view. The RL and TL sedans are faster, nimbler, and sexier than the duo they supplanted, the misfit RSX has retired, and the fresh RDX is staking new territory. With the identity crisis of its teen years safely behind it, 21-year-old Acura already knows what it wants to be.Now it's the MDX's turn to get with the program. Born for 2001 as the more legitimate replacement for the old Isuzu-sourced SLX, Acura's first self-made SUV was a sales star and a critical coup, and wasn't easy to fault. Still, where other Acuras go, the MDX must follow, so the designers saw fit to move it from middle of the road into the fast lane.In fact, they took it all the way to the track - Germany's Nurburgring, proving grounds for the most serious machines - to test and develop the chassis. They later unveiled it to Americans on our own tracks, bringing along European competitors from BMW and Volvo that represent the MDX's performance benchmarks.