We almost got through an entire week without having a run-in with a Porsche Puritan.

But on the last night, two blocks from home, there's one of them waiting for us at a stoplight. He, and unfortunately, it's always he, is behind the wheel of a garage-kept Targa, air-cooled, of course, 993 generation, white paint, fiddling with the manual shifter, enjoying the evening breeze.

He marks us as soon as we pull up in the Guards Red 2006 Porsche 911 Carrera Cabriolet, our left arm lounging on the open sill, our right hand relaxing at 3 o'clock. We've got an automatic transmission, the Tiptronic S, and we're not even trying to hide it.

Don't need to. This automatic 911 convertible runs to 60 mph in 5.2 seconds, quick enough to educate Mr. 993 when the light turns green.

No less of a 911
Out-dragging somebody else's 911 just to prove it's OK to buy one with an automatic is hardly the point. It's about classic body lines, a rear-engine layout, phenomenal handling. But it's even more than that. It's the unquantifiable sensations that only a 911 can deliver.

Like all other 997-generation 911s, the Tiptronic Cab has the body, the rear-mounted boxer six and the reflexes. But a few of the sensations are muted.

Not that you'd ever care in the city where the 911 Carrera Cabriolet dominates any traffic situation. At first, 325 horsepower and 273 pound-feet of torque seem modest in a car with an $81K base price. Then, you realize the 3.6-liter engine revs with the fervor of a superbike motor but has loads more of everything to throw around. Distinct Porsche exhaust sounds are nicely calibrated for open-top driving — subdued at low rpm, yet loud enough to cut through urban chatter at high revs.

Leaving the five-speed automatic transmission in "D" works just fine for commuting. It's plenty smooth and there's no waiting. However, hitting the "sport" button on the dash unlocks a more abrasive side of its personality in which firm redline upshifts are the norm. Throttle response is also punchier.

Buffered in manual mode
Running hard on back roads, though, you'll want to use the manual mode, and that's where the Tiptronic S disappoints.

Tapping the "+/-" buttons on the steering wheel is easy enough, but even in "sport," gearchanges never occur exactly when you think they will. Usually that means slower, and when you're trying to accelerate out of a corner, slower is frustrating.

Consider that our rear-drive 911 Cabriolet weighed less than 100 pounds more than the all-wheel-drive C4 coupe we tested last month but took seven-tenths of a second longer to hit 60 mph and sixth-tenths longer to pass the quarter-mile mark (13.7 versus 13.1). With the harder launch and faster shifts possible in a manual-shift Cabriolet, this gap would narrow considerably, even without the C4's wider track and tires.

More importantly, it just isn't as much fun with a computer mediating the emotional connection between you and your 911. Plus, Porsche makes you pay $3,400 extra to get the Tiptronic S.

Corners flat, stops yesterday
While you're at it, you could also spend an additional $2 grand to equip your Carrera Cabriolet with Porsche's active suspension system (PASM). For another $8 grand, you could fit it with ceramic composite brake discs.

But there's no need.

Just like the coupes we've tested, the Cabriolet turns in smartly, exhibits minimal body roll and, with Porsche Stability Management (PSM) on, will follow your lead on a twisty road. However, the less rigid convertible chassis is more sensitive to midcorner bumps than we'd like. Steering is extremely precise, though, and the 18-inch Michelin Pilot Sport tires are high on stick.

Turning off PSM is the fastest way through the slalom, and at 70.5 mph this is among the top 10 fastest cars we've ever run through the cones. Disabling PSM is also the fastest way off the road if you're not careful, so be ready to catch the tail.

Although this was the heaviest of the 997-generation 911s we've tested, it stopped shorter from 60 mph than any car we've ever tested. Ever. Just 102 feet.

Pedal feel is very firm, but effort builds as progressively as the plot of a Michael Crichton novel. Makes for dull reading, but as brakes go, this is perfection.

Compromises on comfort
As well as the 911 Cabriolet handles, its harsh ride on rough pavement will give pause to all but the Porsche Puritans. It may be in the same price range as the Mercedes-Benz SL and BMW 650i drop tops, but the 911 just isn't like those cars. It doesn't relax. Its suspension never stops transmitting feedback. Its steering never goes into a coma on-center. Some buyers will be drawn to its lack of compromise; others will be turned away.

Then, there's the wind. Lots of it, and the flimsy standard windblocker isn't much help. Unless you want to drive with the windows up, your only option is to stock up on detangler and blast the heat.

Although we like the 911's driving position, we identified one complication associated with having the Tiptronic S transmission onboard: The dead pedal is a bit too high, and since your left foot basically does nothing in an automatic 911, it can get tiresome to have it here for hours on end.

Stuff you may not need
Our 911 Cab tester was loaded with $13,000 worth of options, most of which were unnecessary. For instance, the full leather interior option puts handsome double-stitched leather all over the dash, but the asking price is a steep $3,365.

Spending $920 for a dash-top chronometer also seems like a waste, though it's part of a package that provides more aggressive mapping for the engine management system, PSM and Tiptronic S, according to Porsche.

Plus, it did come in handy for timing the standard power top's operation: 14 seconds to open, 19 seconds to close. We wish there was a warning beep when the top completed the lowering process, because if you don't release the button at just the right point, the windows automatically go back up.

One surprise in the cockpit was the generous amount of storage space. We kept cramming CD cases, snacks and sunblock into the deep, covered door bins but never ran of room.

Know what you're getting
It may not have the rigidity of the coupe, but the 2006 Porsche 911 Carrera Cabriolet is no less intense. And, although we would never say this to Mr. 993's face, you're not missing out on much if you order the Tiptronic S automatic instead of the six-speed manual. At least not when it comes to measurable performance.

You do lose some of those unquantifiable sensations that come with stirring the gears yourself. To us, that's too big a sacrifice, but for many buyers it's an acceptable price to pay for the ability to send a text message while accelerating away from a stoplight.