Guess that makes the S4 the jealous one.
Sure they both ride on the same platform, share the same engines and transmissions, but despite having those common genes, it's the new 2018 Audi S5 Sportback that outshines its S4 sedan sibling. The differences are obvious. The S5 Sportback (and the lower trim and also new A5 Sportback) are the four-door coupe/rear liftgate versions of the A4/S4. Think of them as a smaller A7/S7. The S5 Sportback is what you'll buy because the S4 isn't emotional enough.
While the latter's exterior design doesn't take any chances, the S5 Sportback has actual style and sex appeal. We like that. In fact, the S5 Sportback may just be the best-looking Audi sedan that'll be in showrooms. Power comes from a twin-turbo 3.0-liter V6 with 354 hp and 369 lb-ft of torque, with power going to all four wheels via an eight-speed automatic.
The A5 Sportback, for the record, gets its juice flow from turbocharged 2.0-liter inline-four with 252 hp and 273 lb-ft of twist. But we prefer the S5's meatier V6. Combined with a stunning interior featuring Audi's Virtual Cockpit, the 2018 S5 Sportback is everything the S4 wanted to be but isn't quite talented enough to make it happen.