2006 Porsche Carrera 4 / 4S

People who like 911s really like 911s. They know every branch, every root, every wrinkle in the bark of the rear-engine Porsche family tree. They can tell optional ceramic brakes at 10 paces (it's the color of the calipers). They can spot power-upgraded models by the shape of the tailpipes. That's how any cult works--and Porsche is feeding the cult with the 2006 997-Series Carrera 4.

The true believer will instantly pick one out from a collection: the C4 and C4S have wider rear tracks than a standard Carrera and S, wider tires, and, in consequence, wider rear fenders that make the cars look more voluptuous. But the difference, at 1.7 inches overall, is subtle. So, if you own that car, you can gladly know your fellow initiates will recognize your discernment.

That's one reason the new C4 is wider. There's another, too. Previously, the extra weight of the 4WD versions meant they were slower than the pure rear-drivers around a dry racetrack. The greater tire and tread width of the new C4 makes it corner faster in the dry than a C2--and a lot faster in the wet.

What else? The transmission (six-speed manual or five-speed Tiptronic) feeds a forward propshaft that mates to a viscous coupling unit with a front differential. The torque split is just five percent to the front in normal running, rising to a maximum of 40 percent if rear traction is under duress. The front axle is the same as the undriven one, save for hubs that accept the driveshafts and higher spring and damper rates to support the extra weight. To maintain fuel-tank capacity, the bulkhead is reshaped (normally, it's the same as the Boxster's) and has a saddle tank installed over the propshaft, an expensive item because it needs two pumps, but it fits in 17.7 gallons. That new bulkhead also gets tandem-servo brakes as opposed to single on the regular car, and the system has the added function of emergency-brake assist. By sacrificing the spare wheel, trunk size also is undamaged, but it's reshaped and can now, Porsche coyly says, hold a crate of beverages.