The 1991 Park Avenue utilized GM's GM C platform until the C-body was dropped in 1997. The Park Avenue was normally powered by the 3.8L 3800 Series I V6, with a special Ultra model using a supercharged version starting in 1992 (a very limited number of 1991 Ultras had the supercharged engine as an option). Many consider the supercharged model to be a "sleeper" due to its exceptional acceleration, despite its large size.
Inspired in great part by the 1989 Park Avenue Essence show car, the Park Avenue's silhouette was often compared to that of contemporary Jaguar Cars and many of its styling cues, including a large 'dollar-grin' grille mounted to the hood, rounded lines, and full-width tail lamps made their way to other Buick models restyled in the 1990s. While not the largest vehicle offered by Buick, as that distinction belonged to the Roadmaster, the Park Avenue was the most luxurious and considered the flagship of the marque.
The next generation Park Avenue debuted as a 1997 model, but many feel that the previous generation (1991-1996) had sleeker lines and when fitted with the optional Ultra package, looked like a much more expensive car than the 1997-2005 models. It is also felt that the interior of the 1991-1996 Park Avenues had a cleaner looking, and more upscale look than that of the second generation.
The base Park Avenue was available in Europe from 1991 until 1996 and varied from the North American version by featuring revised taillights with amber lenses and larger license plate opening, amber parking lights, front side marker lights relocated from below the cornering lights to behind the front wheels on the front fenders, larger outside mirrors and a flat hood ornament to meet contemporary European regulatory and safety standards.
An updated Park Avenue was released in 1997, still a C-body but new in 1997, it is a similar platform to the Buick Riviera's G-body. It was for the first time basically the same size as the H-body Buick LeSabre, this generation was powered by updated Series II variants of the indomitable 3800 Buick V6 engine. As before, only Ultra models were supercharged. The base trim featured a hood ornament while the Ultra had a less conspicuous tri-shield inset in on the upper edge of the grill.