2007 Mercedes-Benz SLR McLaren

If the idea of a special edition of an already limited-production car strikes you as overkill, you simply don't comprehend the need for exclusivity that infects the ultra-wealthy. After all, some 1100 Mercedes SLR McLarens have been sold since 2004. Members of the Gulfstream class want something more special.

The partnership of Mercedes and McLaren has responded with this 722 Edition. Only the automotively enlightened will comprehend this moniker's meaning. The numbers 722 were worn by the 300SLR in which Stirling Moss won the 1955 Mille Miglia, averaging 98 mph over public (most of them closed) roads in northern Italy. The SLR's starting time was 7:22 a.m., hence the number.

In keeping with that racing connection, the SLR 722's supercharged V-8 is reprogrammed, getting an extra 24 horsepower and 30 pound-feet of torque. It also gets bigger (15.4 inch) carbon front brakes, lighter wheels, aluminum shocks with 20-percent-stiffer damping, and a higher-downforce carbon-fiber front splitter paired with more angle on the movable rear spoiler. All told, these changes, along with less carpeting and sound deadening, shave a claimed 97 pounds from the SLR's not insubstantial mass.

Mercedes also claims these changes increase top speed from 207 to 209 mph and cut the 0-to-62-mph sprint from 3.8 seconds to 3.6. We don't doubt the claims, and the lusty-sounding V-8, which is still coupled to a five-speed manumatic gearbox, produces massive thrust whenever you want it.

Exploiting the 722's immense performance on winding public roads is, unfortunately, less than satisfying. The stiffer suspension never settles down enough to encourage approaching the car's limits in an otherwise smooth corner. Similarly, the SLR's steering has a blend of direct action and high effort that makes it difficult to carve a smooth line or make subtle midcorner adjustments to the car's path.

Dial your speed back a few notches, though, and you are seduced by the view over the endless hood and the beautiful interior with its carbon-fiber trim, rich charcoal hues, and contrasting red stitching. For buyers of the SLR 722s — only 150 will be built, at an expected cost of $480, 000 each — that will likely be sufficient virtue.