While it would have been easier to simply bolt on a turbocharger and call it good, the MazdaSpeed team has taken a much more comprehensive approach to the engineering behind the 2006 MazdaSpeed 6. Virtually every system has been extensively redesigned, starting under the hood. Here you’ll find a turbocharged and intercooled version of Mazda’s excellent 2.3-liter four-cylinder engine that pumps out an impressive 274 horsepower and 280 lb.-ft. of torque.

To coax those additional 114 horses out of the stock four-banger, MazdaSpeed engineers developed an injection system that sprays fuel directly into the combustion chamber. This DISI technology (pronounced “dizzy,” which gets it our vote for Most Amusing Automotive Acronym since Toyota’s TRD) makes for a denser air-fuel mixture that results in better low- and mid-range torque, reduced emissions, and improved fuel economy. The MazdaSpeed team’s decision to use a slightly smaller turbo also has significant benefits, allowing the 15.6 pounds of boost to come online at just 2,500 rpm. To make sure the rest of the engine was up to the abuse such horsepower invites, engineers replaced hundreds of parts with beefed-up versions including a stronger crankshaft and connecting rods.

To put all this power to the ground, the MazdaSpeed crew jettisoned the 6’s front-wheel drive set-up in favor of a new all-wheel drive system. This system automatically switches between three modes – Normal, Sport, and Snow – to send available torque to where it can do the most good. In the Normal mode most power goes to the front wheels, while the Sport and Snow modes can vary the power distribution between 100 percent front and a 50-50 front/rear split. The only transmission is an excellent close-ratio six-speed manual. While the fact that this shift-it-yourself gearbox is the only transmission offered may put a crimp in sales, we think it’s a fine way to say “Posers need not apply.”

Because a sports sedan that only goes fast in a straight line isn’t much fun, the MazdaSpeed 6’s suspension also received a thorough reworking with firmer springs and shocks and larger-diameter stabilizer bars. Front and rear crossmembers were added and suspension mounting points were reinforced to provide the stiffness necessary to make the most out of the hardware upgrades. Engineers also massaged the ratio of the variable power-assist rack-and-pinion steering to deliver better feel and quicker response. Stopping chores are now handled by a beefed-up braking system, including 12.6-inch ventilated discs up front and 12.4 solid discs in back.