The all-new 2018 Audi A5 and S5 Cabriolets made their big North American debut at the Detroit Auto Show with evolved design inside and out and two new more powerful engines under the hood.

Evolutionary in their design as always, the new Audi A5 and S5 Cabriolets come with many of the design and technical upgrades the new A4 sedans do but come with a fully powered cloth soft top that can lower in 15 seconds even at speeds up to 31 mph.

It stows cleanly under a hard tonneau cover for a finished and premium style when down. It can raise almost as fast and when up offers excellent sound and thermal insulation from the elements with multiple layers.

Similar to their A4 sedan cousins, the A5 and S5 Cabriolets have body structures some 40 percent stiffer which should improve cowl-shake and give a more solid feel on the road. Better still, they are up to 99 pounds lighter as a result of increased use of high-strength steels and aluminum in the body.

Powering the A5 cabriolet is a more powerful 2.0-liter four-cylinder engine good now for 252 horsepower and 273 pound-feet of torque exclusively paired with a seven-speed S tronic dual-clutch automatic transmission. Audi says that means 0-60 mph in 6 seconds flat.

If power is your trip, the the S5 Cabriolet is the one you want, now with a 3.0-liter turbocharged V6 with 354 horsepower and an impressive for its size 369 pound-feet of torque. That brings your 0-60 time down a few ticks to 4.8 seconds. Shifting gears here happens with an eight-speed Tiptronic automatic transmission.

Both of the Cabriolets come standard with Audi’s quattro all-wheel drive. With a self-locking center differential the torque split is 40:60 front to rear when in all-wheel drive mode. Wheel-selective torque vectoring comes by way of its braking system.

A five-link suspension both front and rear sharpens handling and precision. The steering rack is now placed vertically at the wheel centers which Audi says improves feel. With the S5 you can option a new variable ratio steering system that adjusts with your speed and/or the drive mode selected.

As these are boutique cars, seating inside is only for four. The dash and interior design is all-new with greater emphasis on sculpted trims and yet more premium material choices from mild to wild. There’s also now an optional 20-speaker Bang & Olufsen sound system with 3D sound and two subwoofers. Woof.

It also would not be a new Audi without a full docket of infotainment and driver assistive technologies available. Front and center is the hot new Audi virtual cockpit display instrument cluster that offers up crisp and customizable graphics in real time backed up by NVIDIA.

The 2018 Audi A5 and S5 Cabriolets arrive here in the North American market this spring with final specs and pricing to be announced closer to that time.