Newest Mercedes AMG Sport model fills a niche we didn't even know was there What is it?  Mercedes' C450 AMG 4Matic is a model we first saw at the Detroit auto show ("Phoenix, Rising," Feb. 2). The car arrives here about the time you read this. If you’re confused about exactly what it is, the idea here -- according to Benz -- is a sporty sedan offering performance between the C400 4Matic, the car the 450 replaces, and the mighty C63.  When we first saw the C300 and C400 we said they were “gorgeous cars from any angle.” That goes for the C450, too. The front end’s AMG air intakes and badges nicely complement the standard C’s long hood and short rear decklid and are a hint something’s goin’ on here beyond the 400. Don’t expect outright C63 performance, though. Think Cadillac VSport or Audi S, or perhaps C63 Lite.  The C450’s 3.0-liter twin turbo V6 develops 362 hp and 384 lb-ft of torque, and Benz says 60 mph should arrive in 4.9 seconds. The car has a lighter exhaust system and drive modes -- eco (including stop/start), comfort, sport, sport-plus and individual -- adjust suspension, steering and powertrain -- including the 7G-Tronic transmission. The 4Matic all-wheel-drive system sends 33 percent of the engine power to the front axle, 67 percent rearward.  The interior is as outstanding as the C300, plus the AMG treatment adds sportier seats, with AMG-specific upholstery trimmed with red contrasting stitching and Designo red seat belts; there’s also a flat-bottom three-spoke napa leather sport steering wheel. Options include even sportier seats and carbon-fiber trim. What’s it like to drive?  We spent a day tooling around the Smoky Mountains on the North Carolina-Tennessee border, sampling some terrific twisting roads, including a quick shot on U.S. 129, aka Tail of the Dragon. The C450 AMG is a delightful cruiser thanks to its hefty torque curve and a suspension setup that isn’t overly harsh -- it’s a comfortable car to cruise in at high speeds. The drive modes really do make a difference here –- spontaneity and dynamics increase as you swing the knob from eco toward sport-plus. Sport-plus is especially fun, with partial cylinder suppression during gear changes and a nice exhaust rumble during downshifts -- pop! pop! Those gear changes are quite a bit quicker in sport and sport-plus modes as you’d guess, as is the steering -- it feels quick and firm with good feedback. Do I want it? If the C63 is too wild for you, this 450 is a really nice balance of composure and high performance. At first we questioned whether Benz needed this car between the C300 and C63 -- it seemed like an unnecessary baby step. After driving it, though, we think it nicely fills what turns out is actually a big gap. Memo to Mercedes: A wagon version would be ideal ... Wes Raynal  - Wes Raynal joined Crain Communications’ circulation department while still in college. When he graduated in 1986, he became a reporter for Autoweek sister publication Automotive News. He has worked as Autoweek’s associate editor, news editor, motorsports editor and executive editor before being named editor in 2009.  Read more »