It was only a matter of hours after Andy Cohen had mailed nearly 300,000 of his beautiful, four-color Beverly Hills Motoring Accessories catalogues full of expensive car gadgets that his phone rang. On the other end was a doctor, a hard-core car freak. He had seen -- had fallen in love with -- the flashy red Mercedes on the cover of the catalogue. How much? the doctor wanted to know.

The car was not a basic off-the-rack Mercedes that had been gussied-up for cover-girl status. It is called the AMG Hammer, a specially modified (by the German Engineering firm of AMG) 300E sedan stuffed with a 5.6 liter, four-cam Mercedes V-8 that develops 355 horsepower. Other statistics on the car include a top speed of 178 mph, a 0-60 time of five seconds flat, a standing quarter-mile time of 13.5 seconds with a speed of 107 mph. Car and Driver recently called the Hammer the "hottest passenger sedan in history."

Cohen, the only authorized West Coast dealer for AMG- altered Mercedes-Benzes, did not hesitate to offer the eager doctor a deal. The price, out the door, was about $160,000, which, bargain hunters will note, is the same one must pay for a Rolls- Royce Corniche, a vehicle that would be squashed into fine English metalwork if it got in the way of a flying Hammer.

The doctor drew not a breath before he pronounced the deal satisfactory and bought the car. Such are the pleasant vagaries of running the nation's most prestigious automotive toy store. Beverly Hills Motoring Accessories, now barely into its second decade, has become the FAO Schwarz, Eddie Bauer, Abercrombie & Fitch and Sharper Image to upscale automotive enthusiasts across the nation. A riffle through Andy Cohen's lush, 68-page catalogue will quickly show why. Consider a pair of Cartier driving sunglasses, in 18-karat gold, for $449, or a tiny, electric-motor-powered Rolls- Royce for your child at $750.

The firm stocks all manner of automotive-oriented watches, including those officially designed and licensed by both Porsche and Ferrari, at prices up to $2,200. Looking for a steering wheel for the old bus? Beverly Hills stocks the best. The famed Italian house of Nardi is well- respected, and my favorite is its Ghana Mahogany-rimmed model with 23-karat gold spokes at $393.95. Gold car trim is a very hot trim item in Beverly Hills these days, so you can find your favorite marque mounted on a key chain ($399) or on earrings ($199 a pair). You can buy $200 18-karat gold trunk emblems for your Mercedes-Benz. A 23-karat gold personalized license-plate frame is only $127.95.

The catalogue is also loaded with wonderful leather goods for the serious enthusiast. Emerson Fittipaldi, the great Brazilian racing driver, has designed a steering wheel for Porsches and Mercedes-Benzes that is hand-stitched in top-grain leather and matches the interior color of the automobile ($499.95).

The kids and dog messing up your floor mats? How about a pair of mouton-wool mats embossed with your favorite car logo? (Sorry, sir, they don't do Nissan Stanzas -- perhaps you'd be interested in the Ferrari flying horse or the Lamborghini bull?)

In all fairness to Beverly Hills Motoring Accessories and its decidedly high-line inventory, there are any number of functional items in the catalogue at fair prices. For example, BHMA car covers, 100 percent cotton and arguably the best in the business, can be seen shielding fine automobiles from Georgetown to La Jolla. Covers are available at $99.95 for virtually every model sold in America. For an additional $20, Beverly Hills will have one made to fit your 1949 International Harvester pickup.

"The car covers are still the core of the business," Cohen says. He is a slight, well-tailored 40-year-old ex-Long Islander who has lived in car Nirvana -- that's Southern California -- for more than 20 years. "I was one of those guys who was obsessed with cars from the time I can remember," he says. "My schoolbooks were covered with drawings and very little else. College was a total bore, and I came west to get into the car business." Initially, he was somewhat wide of his mark. Desperate for work to support his commitment to drag racing, Cohen sold linen tablecloths to department stores. Then he and a friend bought an auto parts store on tree-lined Robertson Boulevard, a few blocks south of Wilshire.

"It was just your basic auto parts store, and we sold batteries and windshield- wiper blades and gaskets for a while," Cohen says. He noticed an increasing demand for car covers and discovered a source for unique, all-cotton versions. Another American success story: The car-cover business boomed, and the auto parts store was sold and moved to another location. The inventory was expanded to include such hardware as alloy road wheels, high-performance tires and other bolt-on items.

Only within the past few years has Cohen offered boutique items and, finally, a national mail-order operation of the highest caliber. Recently he opened his AMG operation, where a small cadre of technicians convert Mercedes-Benzes into flashy, skirted, winged wonders for the likes of Reggie Jackson and assorted movie types.

Is this fun for Andy Cohen? You bet.

Is this fun for his customers? You bet.

Whether he's at the wheel of his full-dress AMG Mercedes-Benz 560SL or driving one of his growing collection of Ferraris, or simply watching his little business enrapture car lovers around the nation, Andy Cohen's boyhood dream has come true. Sure, one might criticize him for pandering to a collection of the most egocentric, self-indulgent automobile owners in the world. Then again, who am I to say that selling 23-karat gold license-plate frames doesn't serve a compelling social need? Either way, it's got to be more fun than hustling linen tablecloths. ::