These five ultimate four-doors prove that sedans can be sleek and sporty too. Which one would you pick for the perfect spring drive?

2010 Porsche AG Panamera Base price $89,800
2010 Porsche AG Panamera Base price $89,800
In 2003, Porsche AG took the bold — and at the time, hugely controversial — step of adding a four-wheel-drive SUV (the Cayenne) to its previously sports-car-only lineup. Purists gasped, but Porsche felt it had to broaden its appeal; some buyers wanted more than two doors as much as they wanted access to the prestige and elite performance capabilities that come with the keys to a Porsche.

The Cayenne quickly became one of Porsche’s most popular models.

But though it’s a potent performer on and off the road, the 4WD Cayenne was never intended to be an all-out sports car like its 911, Cayman, and Boxster siblings.

Something was still missing from the Porsche portfolio.

With the introduction of the 2010 Panamera sport sedan, Porsche fills in that gap with a machine that offers the no-compromises driving experience of a high-performance coupe in a body that just happens to have four doors.

The car sits low — the top of its roof is only about four-and-a-half feet off the ground (55.8 inches). That’s nearly a foot lower than the roofline of the current Cayenne and within inches of the race-car profile of the current 911 (51.6 inches). And though it has four doors, the Panamera is designed to seat only four people, not five. In the back, you’ll find a pair of sculpted sport buckets, not a three-across bench as in virtually every other luxury sedan. But luxury is not by any means overlooked. Those contoured back buckets are available as eight-way adjustable with seat warmers and coolers, and there is a refrigerated compartment tucked nearby for perishables.

To complete the über-luxury ensemble, select the 16-speaker Burmester surround-sound audio system and “ruffled” ultra-premium leather upholstery.

Under the Panamera’s 911-like hood, meanwhile, lies a 4.8-liter all-alloy V-8 that produces between 400 and 500 horsepower (in Turbo form). It is the first V-8 to be put into a Porsche sports car since the old 928 series, which was discontinued after the 1995 model year. The Panamera shares another feature with the historic 928: Its engine is up in front rather than tucked behind the driver, as in the mid-engined Cayman/Boxster and the rear-engined 911.

The front-engined layout meets the design and utility needs that customers expect in the luxury sedan market, and the V-8 engine was necessary to provide the 4,300-pound sedan with the bottom-end grunt (as well as high RPM horsepower) necessary for 911-like acceleration.

How 911-like?

The standard car (without turbocharging) can blast to 60 mph in 4.9 seconds while the more powerful Turbo Panamera will get you to the same speed in exactly four seconds flat. You can keep track of the stats via programmable in-car “chronometer” stopwatches that record your sessions — on street or track. The fierceness of the engine and the firmness of the Porsche Dynamic Chassis Control suspension system are also fully driver-adjustable — ready for “The Ring” or a gentle commute home from the office — at the touch of a switch.

The Panamera’s power flows to the rear wheels (or all four, if you choose the optional AWD-equipped 4S model) via a seven-speed Porsche Doppelkupplungsgetriebe (PDK) double-clutch manual gearbox that shifts automatically. Some may grumble about the lack of a third pedal and a clutch, but Porsche says the PDK manual transmission can outshift anyone whose last name isn’t Schumacher — and it’s more precise and consistent besides.

The Panamera even has a green streak. Its engine will automatically turn itself off when the car comes to a stop at a traffic light or when you’re stuck idling in traffic and restart itself automatically when it’s time to get moving again. Exactly like a current Prius or Insight hybrid but a lot more fun when the light turns green.

2011 Jaguar XJ Base price $71,650
2011 Jaguar XJ Base price $71,650
How do you update an icon without losing the iconic look — and the buyers who revere the icon?

The first toe in the proverbial water was 2008’s XF, which replaced the very traditional-looking “Old School” S-Type midsize sedan. It was an extremely risky move. Would Jaguar purists object and abandon the brand? And even more importantly, would Lexus, BMW, and Mercedes buyers like the new XF enough to cross shop? The Motor Gods smiled upon Jaguar. Current Jaguar owners did not curl their lips at the XF’s sportier, younger-looking (but still “Jaguar”) silhouette. And potential prospects who hadn’t even considered a Jag in years were showing definite interest.

The 2011 XJ completes Jaguar’s model lineup makeover, offering buyers similarly updated cosmetics in a larger, even more opulent package. It combines modern British elegance — including Satin American Walnut veneer trim panels, foot rests, and drop-down wood-paneled trays for the back-seat occupants — with the very latest in high-end telematics (hard drive-based navigation system, Bluetooth wireless, 1,200-watt Bowers & Wilkins stereo with 14 speakers) for the Total Jaguar Experience.A 385-hp 5.0-liter V-8 is standard, but buyers may upgrade to the supercharged version of the XJ, which ups the under-hood ante to 470 hp. An extended wheelbase XJL offers backseat occupants more legroom than most luxury cars provide for front-seat occupants.