Fun fact: The RS5 Sportback is the first vehicle in Audi's history to launch in the United States before any other market. That's partially because the automaker sees the US as its top priority for new Audi Sport models, especially since we don't get the sweet, sweet RS4 and RS6 cars sold abroad. But really, the biggest driving force behind this US-focused launch is that Audi's A5 and S5 Sportback models handily outsell their coupe and cabriolet counterparts in the States, and the company expects the same to be true with the new RS5.

The sooner those hatchbacks get here, the better. Because just like with A5 and S5, the RS5 Sportback is absolutely the one to get.

No performance loss

Okay, that's not technically true. Audi quotes the RS5 Sportback as having a 3.8-second 0-60 acceleration time, while the RS5 Coupe hits 60 miles per hour in 3.7 seconds, mostly due to the five-door's 89-pound weight penalty and slightly increased coefficient of drag. That said, having launched the hell out of both models, I assure you this one-tenth-of-a-second discrepancy is completely imperceptible from behind the wheel.

The greatness starts under the hood, where you'll find Audi's 2.9-liter twin-turbocharged V6. No, it's not as magical and wonderful and perfect as the naturally aspirated 4.2-liter V8 of Audi's prior RS5 models -- not to mention the 4.0-liter V8 Mercedes uses in its AMG C63. But with 444 horsepower and 443 pound-feet of torque on offer, the latter of which comes on strong at 1,900 rpm, it's certainly no weakling. In fact, at 3.8 seconds to 60 mph, the all-wheel-drive RS5 Sportback is quicker than its four-door Mercedes-AMG C63 S and BMW M3 rivals.

An eight-speed automatic handles shifting duties, and while you'd think a dual-clutch gearbox would be just the ticket for an RS model, I have no complaints about this ZF-sourced Tiptronic transmission. A conventional torque converter means off-the-line starts are as smooth as they are powerful, and when left to its own devices, the Tiptronic executes buttery shifts in Comfort mode and crisp, responsive cog-swaps when you're giving it the beans in Dynamic. Steering wheel-mounted paddle shifters offer quick up- and downshifts for folks who'd rather choose their own adventure, though the plastic pieces themselves don't offer any real tactile satisfaction.

Every RS5 Sportback comes standard with 19-inch wheels wrapped in 265/35-series summer tires, but Audi says it expects most people to step up to 20-inch rollers, with their grippier 275/30-series rubber. The larger rolling stock doesn't noticeably increase harshness over small pavement imperfections -- of course, the RS5's suspension is pretty stiff to begin with. The Quattro all-wheel-drive system defaults to a 30:70 front/rear power split, and can send as much as 85 percent of the available thrust rearward, where a standard sport differential can redirect torque side to side as needed.

You'll want the optional Dynamic Package for its RS sport suspension with Dynamic Ride Control, which allows you to tailor the ride quality to different levels of firmness. But you'll really want it so you can unlock the Dynamic Steering option, which offers variable assist and ratios in Comfort and Auto modes, but uses a fixed 13.5:1 ratio in Dynamic mode, for confident, predictable response -- though it still lacks real communication through the wheel. The Dynamic Package also gets you a sport exhaust, which sounds killer, though I wish Audi let a bit more of that sweet rear-end roar permeate the cabin. You get a lot of "enhanced" engine sound inside the cockpit, but at least passers-by can enjoy the soundtrack.

A Dynamic Plus Package ups the punch with carbon ceramic front brakes and an increased 174-mph top end, both of which are pretty much unnecessary unless you're regularly taking your RS5 Sportback to track days. Of course, while running at 165 mph on an open stretch of unrestricted German autobahn, I'm endlessly thankful for the impressive, surefooted power of those ceramic stoppers when the slow-moving Peugeot people mover unexpectedly moves into the far left lane.

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That said, this sort of high-speed grand touring is really where the RS5 Sportback is most at home. Enjoyable as it is on winding roads through the Bavarian Black Forest, I find the experience a little too buttoned-up for its own good. Sure, the rear end easily rotates with the stability control set to ESC Sport, but since 60 percent of the Sportback's weight is situated over the car's nose, the RS5 has a tendency to dive under braking, shifting weight off the rear axle despite the majority of the car's power being sent to the back. A little more balance, a little more steering feel and a little less virtual engine noise would do wonders.

As a sporty GT car and superb daily driver, you could certainly do worse than an RS5 Sportback -- I'll take this Audi over the too-numb BMW M3 any day. But if it's thrills and chills you seek, the Mercedes-AMG C63 will likely offer more smiles per mile.

Form and function

The Audi's biggest advantage over its German rivals, and indeed, the reason you might buy one instead of an RS5 Coupe, is the added versatility afforded by that Sportback shape. Raise the power liftback and you'll find 21.8 cubic feet of space -- double that of the two-door RS5 -- which easily swallows a couple of large suitcases and backpacks. Fold the back seats flat and cargo volume increases to a seriously useful 35 cubic feet.

Beyond the increased cargo-carrying abilities, let's not forget, the Sportback is better suited to carry people. Rear-seat passengers get an extra inch of headroom and an additional 2.4 inches of legroom compared with the coupe, and a second set of doors means they don't have to do the ungraceful seat-tilt shimmy in order to access those back seats. Sportback models also add a pair of USB ports so rear riders can keep smartphones and tablets good and charged.

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Your eyes may prefer two-door shapes, but I actually think the RS5 Sportback is a better-looking car, full stop. I can't get enough of that graciously sloping roofline and short rear deck, punctuated by the subtle, RS5-specific lip spoiler. Dimensionally speaking, the Sportback is 2.3 inches longer than an RS5 Coupe, and is only an inch taller overall.

You can order the Sportback with all the same appearance packages as the RS5 Coupe, including the Black Optic Package, Black Optic Carbon Package or Matte Alu Optic Carbon Package, all of which add unique 20-inch wheels and offer their own touches to exterior bits like the front lip, side sills and decklid spoiler. You can get black Audi rings and exterior badges, too -- something new for the Sportback, though don't be surprised if this option also shows up on the 2019 model year RS5 Coupe.

Same comfort, more standard tech

Aside from the rear compartment, the RS5 Sportback's cabin is no different from its coupe kin. You get the same RS sport seats (with heat and massage), carbon-look inlays, aluminum trim and a panoramic sunroof, standard. In typical Audi fashion, the cockpit has a generally clean design, with a simple row of climate controls below the central 8.3-inch screen. Audi's MMI infotainment system is controlled by a large dial with shortcut buttons in the center console, and bundles Apple CarPlay, Android Auto and a Wi-Fi hotspot.

Audi says the majority of RS5 Coupe buyers are going all in on tech options, so it just decided to make things like the excellent 12.3-inch Virtual Cockpit display, embedded navigation and the internet-enabled Connect services standard on the Sportback. Wireless smartphone charging and direct tire pressure monitoring are also added to the list of 2019 RS5 Sportback standard equipment.

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A no-compromise offering

The added tech equipment means the 2019 Audi RS5 Sportback will carry a $74,200 base price when it arrives in US showrooms later this year, not including $995 for destination. Yes, that's a $4,300 increase over the $69,900 RS5 Coupe, but, again, almost no one is buying the coupe without these options. I'll bet dollars to doughnuts a similar price/equipment increase is in store for 2019 model year RS5 Coupes, too.

Really, Audi's mission is to offer the same great RS5 package across two body styles; the Sportback adds a welcome heap of daily usability with no tangible performance trade-offs. Plus, it's sort of in a class of one -- BMW doesn't do an M4 Gran Coupe, and the Mercedes-AMG C63 sticks to traditional sedan and coupe shapes. That means the Sportback might appeal to more than just would-be RS5 Coupe buyers. And for Audi, that's a total win-win.

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