Less than a dozen were made.
In case you missed it, GM has axed the mid-size Buick Regal car model line in North America following the sale of Opel to PSA Peugeot Citroen - which makes the vehicle in Germany. That means no more tasty Buick Regal TourX station wagon, yes, but there's another unfortunate casualty of the model line's discontinuation: the Buick Regal Sport Touring, or "ST" model.
The Sport Touring appearance package for the Buick Regal sedan launched for the 2020 model year, with production starting just as GM pulled the plug on the whole model line. The result of this less-than-ideal timing is that just a single-digit number of Buick Regal STs managed to roll off the line at Opel's production facility in Rüsselsheim, Germany, Motor1 has learned from Buick spokesperson Stuart Fowle.
For comparison, the Ferrari 250 GTO - a very rare, vintage sportscar that routinely fetches tens of millions at auction - counts 36 examples produced between 1962 and 1964, making it positively common by Buick Regal ST standards.
Not that one should ever compare the Regal ST to the 250 GTO, because despite its name and the comparisons it might invite with Ford's performance-oriented ST models, Buick's "ST" moniker only denoted a special appearance package for the mid-tier Buick Regal Essence trim. It delivered exactly the same performance as the more standard Regal models, with a turbocharged 2.0L four-cylinder pumping 250 horsepower and up to 295 lb-ft of torque through a standard torque-converter automatic transmission.
The Buick Regal's Sport Touring appearance package comprised a black grille, a subtle deck-lid spoiler, special ST badging, and 18-inch alloy wheels finished in gloss black. The single-digit number of examples produced left the factory in the first half of 2019, Fowle told Motor1, and the model's discontinuation was so abrupt that even GM didn't bother to commission any official photographs.
In other words, we can't even show you what the Buick Regal ST looks like. If that doesn't make it an exceptionally rare bird, we don't know what would.