During the past two decades, Cadillac has struggled repeatedly to invent itself with new designs, new technology and new, higher performance powertrains. That comes to a peak with the arrival of the new Blackwing in U.S. showrooms.

The fastest and, Caddy claims, most nimble products the brand has ever sold, should impress anyone taking their measure — whether by stopwatch or by the pure, seat-of-the-pants feel of launching from 0 to 60 in as little as 3.4 seconds.

But the arrival of what are more formally known as the V-Series Blackwings also has a distinctly bittersweet feel. The CT4-V Blackwing and CT5-V Blackwing, a spokesman confirmed in an e-mail note, will be “the last internal combustion engine sedans that Cadillac will build.” Going forward, General Motors’ most exclusive brand will switch to battery propulsion.

What a way to go.

Big power under the hood

The CT5-V Blackwing is powered by an upgraded version of GM’s 6.2-liter supercharged V-8, here making an eye-popping 668 horsepower and 659 pound-feet of torque. That’s enough to get it from 0-60 mph in a mere 3.4 seconds when paired with a 10-speed paddle-shift automatic transmission.

You’ll sacrifice two-tenths in the sprint if you opt for one, but Caddy has been kind enough to end a century run of internal combustion engines by also offering a 6-speed manual option. Either way, top speed is more than 200 mph, making this the fastest Cadillac ever.

“For nearly two decades, enthusiasts have told us how important it is to have the control of a manual gearbox in their performance sedan,” said Mirza Grebovic, Cadillac performance variant manager. “The ability to choose the driving experience they want is a luxury in and of itself, allowing them to feel more connected with the vehicle.”

The smaller CT4-V Blackwing makes good with a 3.6-liter twin-turbo V-6 rated at 472 hp and 445 lb-ft of torque. Low-inertia turbos, the automaker notes, help deliver plenty of power at low revs. As with its bigger brother, the subcompact delivers some impressive numbers: the automatic model hitting 60 in 3.9 seconds, the stick in 4.1. It tops out at 189 mph. And, for those who dream of launching a Caddy down the quarter-mile, it’ll hit the traps in 12.14 second, at 117 mph.

(And for those comparing stats: the 11.30 second quarter-mile of the CT5-V Blackwing is the same as the Ford Mustang Shelby GT 500.)

“Driving is always a blend of the quantifiable and the subjective, and in both regards, the new CT4-V Blackwing and CT5-V Blackwing deliver like few other luxury sport sedans,” said Grebovic. “They’ve got the numbers to stand with the world’s best, but they also transcend the stopwatch with the sort of satisfying driver experience that cannot be defined by lap times alone.”

Fast paired with great handling and comfort

In today’s world, straight-line acceleration can only be part of the story. And Cadillac spent a lot of time making sure the Blackwing models will be able to run laps on the track, as well as cruise smoothly down the highway. Both models feature electronic limited-slip rear differentials, a magnetic ride control suspension and other improvements to ride and handling. They ride on Michelin Pilot Sport 4S tires designed specifically for each Blackwing model.

Buyers of what is being billed as a limited-run series will be offered the option of upgrading what are already the largest-ever brakes on a Cadillac to a carbon-ceramic package. And there’s an available carbon fiber aero package that, the automakers claims, “delivers the highest downforce in V-Series production history.

Of course, this is a Cadillac, and not just some mainstream muscle car. So, there are all the requisite luxury elements: stitched, heated and cooled leather seats, carbon fiber and metal accents, big touchscreen infotainment systems, wireless Apple CarPlay and Android Auto, and so on. There’s an optional head-up display on the CT5-V Blackwing, and a high-performance steering wheel on its little brother. Both offer “available” performance data recorders.

The CT4-V Blackwing starts at $59,990, though you can quickly run it up to an MSRP of $87,775 when fully configured. The CT5-V Blackwing starts at $84,990 and a fully configured MSRP of $125,980.

Change is coming

But back to the somber note that we began with. This will, indeed, mark the end of an era for Cadillac, the brand that really made the internal combustion viable more than a century ago by incorporating the very first self-starter. Going forward, the brand intends to switch to battery-electric propulsion. That transition begins with the arrival next year of the Cadillac Lyriq.

The initial, single-motor version will push 340 hp and 325 lb-ft through the rear wheels. But a twin-motor variant is in the works and, considering what we’re seeing with other all-electric luxury models, that version of the Caddy SUV very well could deliver sub-4 second 0-60 times.

Cadillac has confirmed it has an array of at least four more BEVs in the works, including an all-electric alternative to the Escalade, as well as a limited-edition supercar flagship, the Celestiq.

While they won’t deliver the aural grunt of the Blackwing series, they could take Caddy performance up to an even more exotic level in the near future.