And though the rear fenders bulged 2.3 inches wider than on other 993s, the front fenders were exactly the same. So, too, the trunklid, roof, doors and windows. But the windshield was slightly larger, and a new lower front fascia presented three large air slots serving the brakes, engine oil cooler, and A/C evaporator.

Engineers strove to optimize aerodynamics and minimize weight with the latest Porsche Turbo. The former goal explained the regular-width front fenders, while the latter was helped by the simplified AWD. Also trimming heft were new 18-inch aluminum wheels with hollow spokes, a Porsche-patented design that saved a total 24 pounds in nasty unsprung weight.

Rim widths were eight inches fore and 10 aft. Respective tires were P225/40s and P285/30s, all Z-rated Pirelli P Zero. Brakes were naturally upgraded -- what else from Porsche? -- going to vented and cross-drilled discs measuring an inch wider and a massive 12.7 inches in diameter, adorned by trendy red-painted calipers.

The new twin-turbo installation was quite different from the hallowed

After spinning the turbines, exhaust gases passed through a large intercooler on each side, then merged to feed the cylinders. Each turbo had a wastegate that limited maximum boost to 11.6 psi. Turbo efficiency was unusually good, because the engine bay was always mildly pressurized by the engine cooling fan.

Also noted a number of premium upgrades for the Turbo version of Porsche's latest M64 engine. Cylinders, for example, were forged for strength under pressure rather than cast, and their cooling fins were machined to optimize airflow. Cylinder heads, pistons and conrods were all reinforced, as usual with force-fed engines, and the valve rockers added tiny hydraulic valve lifters for easier adjustment. Even the cooling fan wasn't overlooked, geared to run 15 percent faster than in other Porsche 911s.

No less care was lavished on the rest of the powertrain. Like the C4, the Porsche Turbo came only with a six-speed manual transmission, but the four intermediate gears got shorter ratios to enhance acceleration, while sixth got "longer" (numerically lower) gearing for quieter, more economical high-speed cruising. Because the front differential left no room for the usual vacuum booster, the Turbo employed hydraulic brakes with a compact electric pump providing pressure at 2,300-2,600 psi. The system also served the clutch, thereby reducing driver fatigue in the everyday grind.