AN aura of nostalgia settled over Ocean Terminal, Tsim Sha Tsui, last week. The reason, Milan Motors, importers of the famous Alfa Romeo marque, held a special exhibition to celebrate three decades of the pretty Alfa Romeo Spyder. The display was primarily aimed at the forthcoming arrival of about 40 beautiful examples of the Spyder's latest evolution, the 2.0i Alfa Spyder. The original Spyder arrived on the scene back in 1966 with its elegant new body designed by the styling house Pininfarina. The new Spyder is a follow-on from the previously designed Giulietta Spyder of 1955. The 1600 Duetto Spyder arrived at the same time as the MGA became the MGB, when Lotus was flying high with the original Elan, and while the Austin-Healy 3000 was thundering around the territory's much less congested roads. This ''Spyder Celebration'' by Milan Motors featured a perfect 1966 Duetto ''boat tail'' in white, lovingly restored and maintained by its owner. The original Spyder was joined by a pretty 1977 Spyder Veloce 2000, with its slightly more defined line and Kamm tail. These were, in turn, complemented by the 1987 Spyder QV (Quadrifoglio Verde), bedecked with deep spoiler and side skirts. All clearly showed the unbroken lineage of the Spyder as it evolved over the years into the latest beautifully proportioned and attractive convertible for the 1990s. For me, the latest Spyder is one of the finest of the series, with fine detailing and colour-keyed spoilers and bumpers, finished off with a splendidly appointed interior. The Spyder of today, if anything, is even better proportioned and more appealing than the original Duetto Spyder. Surely that's a triumph of evolution over revolution. Performance, however, is not as red-hot as it could be with the splendid Alfa Romeo power plant now constricted by the addition of a modern three-way catalytic convertor. The car is rated 120 bhp at 5800 rpm, while the new Spyder makes the 0-100 kilometre per hour dash in 10.4 seconds, howling on to a possible top speed of 190 km/h. In all, it is not that more lusty than the 1966 Duetto which managed 109 bhp at 6000 rpm and a top speed of 170 km/h from a 1600 cc engine. Speed and power, however, are not the major raison d'etre behind this gem of a car.