Used 2009 Maserati Quattroporte

There's a naughty button on the dashboard of the 2009 Maserati Quattroporte Sport GT S that's marked "Sport." Give it a prod and several things happen. The engine and gearbox have their brains rewired, and two exhaust valves open to give full voice to the big V8. The result is a noise quite unlike any other luxury sedan. It is extraordinarily loud and gloriously obnoxious — pure Maserati.

This exhaust trickery — and the increased thrust that comes with it — is the signature feature of Maserati's new flagship. The GT S is a development of the Quattroporte S that debuted last year, and it rivals the Audi S8 and Mercedes-Benz S63 AMG. Developed for plutocrats who want to drive and arrive, the 2009 Maserati Quattroporte GT S remains a more luxurious and beautiful sedan than its rivals, but now it's also a truly sporting one. Maserati reckons the Sport GT S will account for up to 30 percent of Quattroporte sales.

If It Ain't Busted, Don't Fix It
When the Pininfarina designers sat down to sketch the Quattroporte, they must have been sipping some splendid Chianti. Even five years and a face-lift on from its original launch at the Frankfurt auto show in September 2003, it remains the finest-looking luxury sedan on sale. No other car could dress such colossal length — the Quattroporte is 201 inches long with a 120.6-inch wheelbase — with such elegance. This Maserati is automotive art, and its sinewy curves are enough by themselves to challenge rivals from Audi, BMW and Mercedes-Benz.

Thankfully, Maserati has employed the "If it ain't busted, don't fix it" mentality to the new 2009 Maserati Quattroporte Sport GT S. A successor to the Sport GT S version of the Quattroporte first introduced at the 2007 Frankfurt Auto Show, it includes a new black grille with concave vertical fins, revised headlights, a pair of oval exhaust tips and 20-inch wheels, but that's about it. Only the cognoscenti will notice, which is exactly how things should be.

(Not Quite) Designer Cockpit
In contrast to the highly engineered, carefully choreographed cockpits of the Audi A8 and Mercedes-Benz S-Class, the Maserati does have the look of designer boutique. There are lashings of leather and suede and the dash can be dressed in Titantex, a bizarre concoction that looks like gray carbon fiber. You can also specify some fairly interesting color combinations, including bright red leather trim that should really be named "tart's boudoir."

There are some lovely details. The aluminum pedals look like sculpture and the suede-upholstered rim of the steering wheel feels great, even if we'd worry about its long-term longevity. But for all its finery, too many bits have still been plundered from the Fiat parts bin. For example, the ignition key looks like it last found service as a treat in one of those exploding Christmas crackers the British love so much, while the multimedia system is irritatingly fiddly.

You also have to compromise on space. There is ample room in the rear seat for a pair of 6-footers, but they won't lounge in quite the same comfort as they would in the Merc or Audi. Nor will they be able to fit quite as much designer luggage in the trunk. You can blame the layout of the car for that, with its V8 engine significantly behind the centerline of the front wheels where it intrudes on the cockpit, although it does deliver the 49 percent front/51 percent rear weight distribution that delivers superior dynamics on the road.

Glorious V8
The GT S employs a version of the 4,691cc V8 featured in the Quattroporte S and Gran Turismo S coupe, Maserati's version of the same fundamental V8 engineered by Ferrari for use by Alfa Romeo, Ferrari and Maserati. Tweaks to the engine management system and a new exhaust have helped liberate an extra 9 horsepower, so the total output is now rated at 434 hp at 7,100 rpm and 361 pound-feet of torque at 4,750 rpm. When you engage the exhaust system's Sport mode, the V8 is extraordinarily loud, especially on the final ascent to the 7,200-rpm redline. Your neighbors will either cheer or throw stones.

This glorious engine has found a soul mate in the six-speed ZF-built automatic transmission. The hardware is familiar — Jaguar and Aston Martin use the same system — but it's been tuned for Maserati. In Drive, the shift action is effortlessly smooth, or you can slot the lever into manual and make use of the shift paddles mounted on the steering wheel.

For the 2009 Maserati Quattroporte Sport GT S, the transmission really does deliver only manual operation in manual mode. Apparently Ivan Capelli, the ex-Ferrari F1 driver now employed as a Maserati test driver, once had a huge accident when a BMW automatic transmission shifted up a gear, so he insisted on full manual control for the Maserati transmission. In manual mode, the gearbox will neither kick down nor change, even when the engine is on the rev limiter. It feels better for it, and the way the system automatically blips the throttle for quicker downshifts is nothing short of brilliant.

Let's Get Sporty
To reflect the Sport GT S's new, sportier disposition, the spring rates for the suspension are significantly stiffer, some 30 percent at the front and 10 percent at the rear, and the ride height has been lowered 0.6 inch at the front and 0.4 inch at the rear as a result. Moreover, the electronic Skyhook active damping has been replaced with a more conventional passive system.

Maserati is happy to admit that the Sport GT S is a clear step beyond the Quattroporte and the Quattroporte S and will only appeal to its more enthusiastic customers. The ride is predictably firm, but it never felt truly harsh, even on the city streets of Modena. Instead, you get a remarkable level of control.

No other 4,387-pound sedan feels this responsive to the helm or disguises its mass with such aplomb. At times, it feels more like an Audi S4 than an S8. This is not a sportier version of a luxury car; it's a genuine sport sedan. And it is genuinely fast. Lean on the new launch control system and this car will scurry to 100 km/h (62 mph) from a standstill in 5.1 seconds, which is 0.3 second quicker than the Quattroporte S. Top speed climbs 3 mph to 177 mph.

Maserati Is for Real
The 2009 Maserati Quattroporte Sport GT S is further evidence of a company on a roll. While the rest of the world wallows in red ink, Maserati has just announced record sales of 8,586 cars for 2008 and record profits of $93 million. This might not sound like much — Chrysler loses more money in a coffee break — but for the Italians it's a big deal. Maserati is finally stepping out from the shadow of Ferrari.

When the Quattroporte Sport GT S arrives in the U.S., the base price will be $133,700. But of course, you'll have to figure in an estimated $2,600 gas-guzzler tax plus $1,500 in delivery charges and $300 for the little extras, so you'll be looking for at least $138,100.

In a way, the Quattroporte Sport GT S is more like a Ferrari than previous versions of the sedan, a little bit more focused on performance. Among all the premium sedans that you might spend something more than $130,000 upon, the new GT S remains the eccentric choice, but while your rational being will lean toward the Audi or Mercedes, your creative brain will ache for the Maserati.

Edmunds attended a manufacturer-sponsored event, to which selected members of the press were invited, to facilitate this report.