The late Gianni Agnelli’s favorite cars went on show at the Museum of the Automobile in Turin, Italy, on March 12, which would have been his 92nd birthday, and will be on display until June 2. Agnelli, who died 10 years ago, was one of the two grandsons of Giovanni Agnelli, founder of the Fiat Group, and was instrumental in his company acquiring Ferrari after Ford failed to do so in the 1960s.

The cars range from a miniature T35-type Bugatti, which the future industrialist used to drive in the garden of his home at Villa Perosa in the hills outside Turin, to a Ferrari 360 Speedway, but he was a great fan of the Fiat Panda—the hyper-utility that was a huge success in Italy and of which he owned 11. He particularly liked the version called Mare (Sea in Italian), for which he had the roof group cut off and replaced by a sort of canvas surrey top. For his official engagements, he used often a 1997 Lancia K transformed into a limousine, with its American-style vinyl-covered roof, a car that was loaned to Queen Elizabeth II for her official visit to Italy in 2000.

The 10-car collection also includes a 1960s Fiat 125, another of his favorites, except when he drove to his winter home in St. Moritz, Switzerland, for which he used a large Fiat 130 estate car with an enormous rectangular enclosed roof rack that he had packed with skis, sticks, boots and the usual paraphernalia. One of the oddball cars on show is a six-seater Fiat Multipla MPV with its roof group taken off, its sides and interior completely reworked by Pininfarina in wood, steel and aluminum with the cockpit similar to the driving position of a motor launch.

Others were standard production models, but modified to his taste, one for business trips in later life with its rear seats covered in exclusive materials by top people’s tailor, Ermengildo Zegna. When car telephones emerged, Mr. Agnelli usually had three of them in one car, one to the right of his seating position, one to the left and the third up front with his driver, necessitating three aerials on the roof. He also liked small drawers in his cars, in which he would keep his packets of cigarettes.

Most of all, Gianni Agnelli liked speed, so just about every car he had was much modified for a sportier drive.