Twenty-five years ago today, the last Buick Grand National came off a General Motors assembly line in Pontiac, Michigan. The event also marked the closing of GM’s oldest plant, and despite the fact that dozens of workers were about to lose their jobs just two weeks before Christmas, the vibe was anything but negative.

It was almost as if the workers involved in building the last Grand National knew they’d be a part of something bigger, and that the final car off the line was more than just another automobile. Now, two and a half decades later, a newly-released documentary called Black Air tells the fascinating story of the car and the mystique surrounding it.

To be clear, “mystique” is not a word we’d often use in association with Buick, but the Grand National was more than just another grocert-getter. Originally conceived as a way to lure younger buyers into Buick showrooms, the designers of the Grand National soon realized that performance was paramount over style.

In other words, a stripe package and chrome wheels wouldn’t be enough to sell cars, though that’s what Buick brought to market in 1982. No Grand Nationals were built in 1983, but the car returned in its beloved black and sinister form in 1984, and it almost immediately began raising eyebrows in the performance car world.

Thanks to a turbocharged 3.8-liter V-6 that cranked out as much as 245 horsepower and 355 pound feet of torque, the Grand National soon proved capable of embarrassing  cars costing significantly more money and adorned with far more prestigious badges.

In 1986, Car and Driver showed that the Buick was faster from 0-60 mph (4.9 seconds) than the Lamborghini Countach (5.1 seconds), the Ferrari Testarossa (5.0 seconds) and even the Ferrari 288 GTO (5.1 seconds). It also beat Porsche’s 928S (5.7 seconds) and 944 Turbo (6.0 seconds).

Despite these impressive credentials, the Grand National was something of an orphan, ignored by both Buick owners and sports car aficionados. Either in spite of this or because of it, Grand National collectors are among the most extreme in the automotive world; after all, Buick may someday resurrect the nameplate, but there will only be one true Buick Grand National.

For its final year, Buick even built a higher-performance variant called the GNX, which boasted performance and handling improvement over base models. Thanks to a larger turbocharger and other modifications, the GNX put out a conservatively-rated 276 horsepower and 360 pound-feet of torque, which made it capable of 0-60 mph runs in a truly impressive 4.7 seconds.

Black Air goes on sale today, and it’s a must-have DVD for any fan of American performance or muscle cars. You won’t find it in stores, so head on over to the GN Movie website to order up your own copy.