One of the things that impressed us while driving a standard 2004 Boxster was its tractability. It motors along with no complaints at very low rpm, making for pleasant cruising around town. Stand on the throttle, and the 2.7-liter engine springs to life, emitting a deep growl (actually more of a rowl) in the upper rev range. The standard Boxster offers plenty of performance for most folks and we'd be completely happy with it, assuming we stayed out of the Boxster S.

Revised for 2003 with Porsche's VarioCam technology and a new engine management system, the standard Boxster's 2.7-liter engine puts out 225 horsepower at 6300 rpm and 192 foot-pounds of torque at 4750 rpm. Boxster can accelerate from 0 to 62 mph in only 6.4 seconds, according to Porsche, an improvement of 0.2 seconds over the 2002 model. Top speed is estimated to 155 mph in the Boxster.

Boxster S gets a bored out version of the same engine, a 3.2-liter that serves up 258 horsepower at 6200 rpm and 229 foot-pounds at 4600 rpm. The added power reduces 0 to 62 mph acceleration times to 5.7 seconds.

At a glance, the Boxster engine is classic Porsche with roots that date to Ferdinand Porsche's early work in the 1930s. The horizontally opposed six-cylinder "boxer" layout offers packaging advantages because the pistons lie flat, which helps keep the center of gravity low. But the Boxster engine represents the state of Porsche art with twin overhead cams, four valves per cylinder, variable cam timing, and liquid cooling.

Boxster comes standard with a wonderful 5-speed manual gearbox, while Boxster S comes with a similarly wonderful 6-speed manual. Porsche's 5-speed Tiptronic S automatic ($3,210) is available for both models. The Tiptronic offers its operator the choice of full automatic operation or fingertip push-button self-shifting. It's the best compromise between stick and automatic on the market and works extremely well, but it's also the most expensive. A manual gearbox provides better performance and efficiency and seems more fitting for the Boxster. We prefer it.

Porsche brakes are legendary and braking in the Boxster is superb. Oversize vented discs are used on all four wheels plus Porsche's excellent antilock system. Porsche Stability Management ($1,235), or PSM, is a recommended option as this anti-skid system can correct skids can help you stay on the road in an emergency handling maneuver.

The Boxster generates impressive grip in the wet, whether braking or cornering. PSM helps greatly in slippery conditions, making it more difficult to make a mistake in this car. You can apply the throttle aggressively in a slippery turn and the stability system will prevent a spin.

As much as we like the standard Boxster, the Boxster S has more power and the engine revs more freely. Both engines sound wonderful at high rpm, generating a classic Porsche sound similar to that of the 911 and Porsche race cars. The Boxster S develops 85 percent of its peak torque at just 2000 rpm, providing outstanding throttle response.

But the real fun lies in the Boxster's precise response to driver commands. Mid-engine balance, an excellent chassis, and firm suspension tuning add up to a level of agility and stability that seems a cut above the Boxster's key competitors. No wrestling is required to guide this roadster down to the apex of a fast turn. It seems to anticipate the driver's intentions without a hint of hesitation or uncertainty. The ride quality is firm, but that adds to its appeal. The Boxster gets the same shock absorbers as the Boxster S, and the standard 16-inch wheels can be upgraded to lightweight 17- or 18-inch wheels.

So, Boxster or Boxster S? It's a much tougher call than it was before the base model was improved and comes down to personal preference. Enthusiasts who appreciate taut handling and quick acceleration performance and drivers who like ripping down mountain roads or autocrossing appreciate the higher state of tune of the Boxster S. Others are quite satisfied with the standard Boxster. While spending a week in Southern California with a Boxster, we never felt a longing for a Boxster S, we never felt that something was missing. If you're unsure, our recommendation is for the standard Boxster. Those who need the performance of the S, and you know who you are, will feel it's money well spent. Others will prefer to bank the cost difference or spend it on options that enhance the standard model.