During our compact luxury sedan Big Test comparison, the Audi A4 won in virtually every category, but it just couldn't win our hearts. Part of that had to do with its design, which showcased Audi's precision and craftsmanship but was mostly devoid of emotion. For the customer who would choose an A4 if it weren't for its sedate looks, there's now the 2018 Audi A5 Sportback to consider.

Audi helped pioneer the modern swoopy hatchback sedan with the A7 and followed that with a four-door version of the A5 for Europe. We didn't get the first-generation A5 Sportback, but Audi has decided to bring the latest iteration Stateside, likely after seeing the success BMW has had with its 4 Series Gran Coupe. The A5 Sportback, along with its sportier S5 sibling, lifts design cues from the A5 and S5 coupe. But Audi has done more than just stretch the roofline and add a couple more doors. The greenhouse has been given a distinctive shape with a rear quarter window that not so subtly bites BMW's Hofmeister Kink style. Original or not, I can't argue with results because the Sportback's profile is gorgeous.

This four door has a sexier silhouette than the A4, but the driving experience is very similar—and that means it's very good. All-wheel drive comes standard on the Sportback, so handling is excellent in any trim. The launch took place in Seattle, Washington, and the Pacific Northwest lived up to its reputation for wet weather by dropping some rain on our drive route. But with the tremendous grip the Quattro all-wheel drive affords, you could hardly tell the pavement was wet at all. Audi's now familiar turbocharged 2.0-liter inline-four provides 252 hp and 273 lb-ft of torque in the A5 Sportback, which was more than enough to get the car moving down the woodsy back roads outside of the city. The engine is backed by a seven-speed dual-clutch transmission that offers buttery-smooth gear changes and shift logic that always has you in the right gear. The tires are a bit noisy on the highway, but the ride was otherwise quiet in all modes when I switched to the S5 with the available S Sport package.

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See all 73 photos

That package adds an adaptive suspension, Quattro sport differential, and larger six-piston front brakes, and it is required if you want Audi's speed-sensitive variable Dynamic steering option. The electronically adjusted dampers are soft and compliant when the road is straight but stiffen up significantly for corners. Turn-in is sharp, and the all-wheel drive enables explosive acceleration coming out of a corner. A fixed sport suspension comes standard on the S5, but regardless of suspension choice, each Sportback is at least 0.9 inch lower than the A4.

Like the S4 and S5 coupe, the S5 Sportback gets a new twin-scroll, hot-V turbocharged, 3.0-liter V-6 mated to an eight-speed automatic. Producing a healthy 354 hp and 369 lb-ft, that single-turbo mill is estimated by Audi to accelerate the S5 Sportback to 60 mph in 4.5 seconds. We'll see what it can really do when we get our hands on one for testing, but it certainly feels quick when taking off from a stoplight. The Quattro system hooks up immediately—even in the wet—sending the car lurching forward quickly but smoothly. There's no real trick to launching the car. It just takes off with no drama and accelerates effortlessly. In Dynamic mode, the gear shifts are subtly more aggressive, transmitting just a tad of harshness to heighten the perception of sportiness. In any mode, the paddle shifters fire off gear changes with dual-clutch-like speed. Both cars, however, suffered from the same disconnected steering feel as other recent Audis we've sampled. Dynamic mode adds steering effort, but no more feedback.

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The A5 Sportback rides on a slightly stretched version of the A4's wheelbase that's 2.9 inches longer than the A5 coupe's. That increased length gives it 2.4 inches more legroom than the coupe. On paper, the backseat is smaller than the A4's, but it's not a noticeable difference. I was able to sit behind my own driving position with room to spare, and headroom in back was adequate for a taller journalist. The standard front seats in the A5 Sportback are comfortable and supportive enough, but the well-bolstered, diamond-stitched leather S sport seats of the S5 were better suited for twisty mountain roads. With either seat, I was able to adjust it to a low driving position and get a decent H-point.

Interior trim in the A5 looks premium enough, with high-quality plastics and metallic finishes surrounding the driver and passenger. Things get really upscale in the S5, though, with our tester coming with carbon-fiber inlays on the dash and center console, Alcantara door panels, and red contrast stitching everywhere. An MMI infotainment system with 7.0-inch central screen comes standard, but an 8.3-inch display with higher resolution is available with navigation and handwriting recognition capability on the control knob. Audi's Virtual Cockpit instrument screen is available for both the A5 and S5, and it looks just as impressive here as it does in the rest of the lineup. Also available is a full-color head-up display, which can be placed high in your line of sight (or low, if you prefer) and features bright, easy-to-read characters.

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Of course, another benefit of choosing the A5 Sportback over the A4 sedan is the rear liftgate. The cargo area offers 21.8 cubic feet behind the rear seats compared to just 13 cubic feet for the A4's trunk. With the seats folded down, that expands to 35 cubic-feet. The rear bench is of a 40/20/40 split folding design, so the cargo area is configurable in a variety of ways. Audi says seating capacity is a big factor for customers when cross-shopping vehicles, so the A5 Sportback only offers seating for five, unlike the A7, which offers both four- and five-seat configurations.

The Audi A5 Sportback starts at $43,575, which is $3,225 more than the price of a comparably equipped Audi A4. But you do get a power liftgate, more cargo space, a panoramic sunroof, and an exterior that's much more interesting to look at. The Sportback's starting price is in lock step with that of the BMW 430i Gran Coupe, but if you want xDrive all-wheel drive you'll have to pay $1,620 more than the Audi. The S5 Sportback starts at $55,375, or $3,880 more than the 440i xDrive Gran Coupe, which makes less power at 320 hp and 330 lb-ft.

The A4 has a lot going for it to stimulate the left side of the brain, with its balance of performance, practicality, refinement, and luxury, but there's not much to satisfy the right side. The A5 Sportback offers virtually the same driving experience as the A4 wrapped in an exterior package that will make you look back longingly every time you walk away from it—with the extra cargo space being an added bonus.