One of the fastest (208 mph) and quickest (zero to 60 in 3.8 seconds) cars on the planet, for a start, and, more important to me, it also has the fastest-operating power top that I know of: down or up in 10 seconds, which beats the previous record holder, the Porsche Boxster, by two ticks. As a convertible driver, I can assure you this is important: when you're motoring to the gym, then the mall, then the post office and home, you don't want to be sitting in a parking spot counting one-potato to thirty-potato while your power top lethargically grinds through its cycle. 

The Mercedes McLaren was developed through a sometimes contentious partnership between the carmaker and its UK-based Formula 1 racecar builder, Team McLaren, and Mercedes' in-house high-performance engine builder AMG. It's made largely of carbon fiber and aluminum. And lots of leather.

The Saks MercMac went on sale yesterday, the 14th, and there are only five for the store chain to sell. What sets them apart and makes them cost about $80,000 more than a straight SLR roadster, therefore, is that the car is a "Special Edition," limited to these five examples, which have unique interiors. Oh, and gold-painted brake calipers, which are those things you see through the wheels, clamped around the brake rotors. If you don't know or care what calipers, wheels, or rotors are, we're talking about the gold things behind the tires. Trust me on this.

You also get a trip to France and a day at the Paul Ricard racetrack, near the Riviera, for some lessons in how to drive a car that'll go faster than most lightplanes. And $10,000 of your purchase price will be contributed by Saks to the St. Jude's Children's Research Hospital, in Memphis, Tennessee.

Now, everybody who's anybody has an ordinary Mercedes MacLaren. If you saw Britney Spears do her no-pants dance, she was at that gynecological moment climbing out of Paris Hilton's SLR MacLaren coupe.  [Uh-oh, my mistake: Britney called to tell me she was climbing out of her own SLR; Paris was just the designated driver.]  But only five people in the world will own a Saks Fifth Avenue SLR MacLaren, and all of them, I am confident, will wear underpants. Since Saks has stores in Dubai and Saudi Arabia, some of them will probably also be wearing hijabs.

What amazes me is that these cars might well be impulse purchases, the retailing equivalent of what happens when somebody goes to an auction and gets crazy. People who decide they need a Mercedes SLR McLaren go to the dealer, put down a deposit, and wait six months for their car to be built. People with more money than sense buy one on a whim from a department-store catalogue.