300kmph super-family time: Audi RS7 Sportback and Mercedes-AMG GT 63 S 4-door

The lockdown's been many things for many people - a chance to sleep and eat better, watch the entire catalogue of streaming TV, finally get around to exercising, or just generally slow down and smell the roses, for a change. For most, it's been a wake-up call. That your time's too fleeting for the 'ol 9-5, perhaps. That there's more to life than video calls and e-mails. And definitely to spend more time with the family - this is one thing that really hit home with my family 2,000km away, across two states.  

And for the life of me, numbskull petrolhead that I am, I can't think of anything that screams quality family time like a once-in-a-lifetime trip to 300kmph. And that's exactly the sort of capability the Audi RS7 Sportback and Mercedes-AMG GT 63S 4-door bring to the family table. They bring a lot more, of course. But one of the big draws is the ability to seat four in absolute comfort and still do the kind of silly speed that's on the bucket list of most every petrolhead. Which means you can very well plonk the whole family in (with some cajoling), or all (three) of your friends, to share in the wondrous, life-changing experience that is a sub-four second dash to 100kmph from a standstill, or even the ultimate bonding that comes from finding a closed off strip of tarmac and achieving terminal velocity. Remember, safety first, especially if you've actually somehow managed to convince your mother to sit in the car. 

Because these two are seriously, scary quick. Quick enough for the reaction videos you're obliged to film to be hilariously genuine shock that two cars this big and luxurious move the way they do. While both have relatively humble origins, with the RS7 based on the A7 luxury sedan, and the GT 4-door essentially being an E-Class underneath (it's not a spaceframe like the GT), both can also shame most supercars in a straight line. Audi claims a 0-100kmph dash in 3.6 seconds for the RS7, while AMG says the GT 4-door will do it in 3.2 seconds. Proper supercar-rivalling numbers, and there's no way you're fitting four people in an Audi R8 or GT R, for example. In fact, with the RS7 available with a proper middle seat for the first time, you could even squeeze in five, while the optional rear seat package in the GT 4-door makes it strictly a four-seater. But since both Rohit and I have family in different cities, we figured we'd give these family-carrying brawlers a test run first, on possibly the only sunny day we've had the entire month. 

Considering the GT 4-door was conceived to be exactly that, I can't help but think the headlights from the GT sportscar would be a better match for the character set by the Panamericana grille. Though, the GT 4-door is suitably wide hipped to trace the lineage. The fixed rear wing in carbon definitely helps it stand out, adding to the coupe-like silhouette otherwise mistakable for a CLS.

It's expensive looking for sure, but not outright aggressive, if that's your thing. It even fires up in a relatively civilised manner, perhaps a sign of the considerate nature of the slightly older buyer who'd be drawn to it. Though you can fix that by opening up the exhaust valves, accessible through one of the tiny digital screen buttons laid out on that V8 console.

Those tiny screens, coupled with the even tinier screen-dials on the steering which switch graphics as you cycle through everything from traction control to drive modes, have to be the sweetest thing about the AMG's cabin – they're inexplicably cool in the same way that folding touchscreen phones are cool. You know they're not really necessary but seem like the best advertisement for the future.

Perhaps most telling of how spoiled by tech we are, the first thing I did when I was done admiring the cabin of the GT 4-door was reach a grubby finger out to the massive central screen and try and pair my phone. It took a couple of swipes before I realised that this iteration of that 12.3-inch screen wasn't a touchscreen. Silly millennial me. No, this MBUX is old-school, with a touchpad just north of the stubby gear lever. Though, I immediately know my mom would approve of the lovely quilted tan leather upholstery. The hard-backed AMG bucket seats, maybe not so much. They fit snugly enough to make your socks jealous, and are something you'd expect in a track-bred sportscar. Elsewhere in this issue, you can see the resemblance the GT 4-door's cabin has to the GT R, so it's definitely bringing you close to the supercar experience, through and through. The wide central console, styled to replicate the banks of cylinders of the V8 under hood, just adds to the drama – there's legitimate thrills before you even get rolling – a rarity in this sedan-with-firepower world.

Before you do, a quick rundown of the eye-watering specs in case the luxurious interiors let you forget you're piloting AMG's most powerful production car. Its hand-built 4-litre twin-turbo V8 is pumped all the way up to 639PS and 900Nm of torque, which explains the low three second timing despite its 2.1 tonne kerb. Not that you'd be able to guess the weight when you're driving it. Somewhat magically, though you're not sitting on the floor, with your shoulders just under the window line you feel like you're part of the car, further keeping you guessing about its weight. The rear-wheel steer doesn't hurt either, shrinking the wheelbase around you. You also realise is that AMG hasn't really softened up the GT 4-door's air suspension, which may or may not earn you brownie points with the fam. The flipside is you really feel everything on the road surface. I swear I even felt the crunch as I drove over an empty plastic packet! The connection to the tarmac is immediate, even through the steering, and unlike any other performance car this side of a two-door. I suppose it's somewhat expected, with the GT 4-door inheriting its under-chassis bracing from the GT R for extra rigidity, as well as its tubular anti-roll bars. 

Passing through the city to meet up with Rohit, all I can actually hear from the GT 4-door is a big sigh and a whoosh every time I nudge the gas for an overtake. The nine-speed wet multi-clutch automatic is perfectly mannered in these situations, keeping that great, big V8 calm and collected. Though, one moment of lapsed patience, and a boot full of throttle over a slippery flyover reveals that AMG hasn't lost the GT R's character through all the refinement – I'm rewarded with a twitch from the tail almost instantly.

Curiosity piqued, I try again. Man, this engine has a serious punch up the revs! All this while I'd been riding the sizable wave of torque down low but you'd be missing the point if you didn't take it right to its redline. Because while power peaks at 6,000 revs, the rising crescendo of the V8 tells you to shift at 7,200 instead. Somehow AMG's even smoothed out the noise and the cracks and bangs on the overrun, making it feel almost dignified in a way. In comparison to the raw, unfiltered nature of this engine's soundtrack on every other AMG I've driven so far, this sounds like the studio version. 

As I pull up to the brand spanking new RS7 pulled over on the highway, I have an overwhelming urge to pull my phone out and take pictures of it. It's stunning in the flesh! In Nardo Grey, it looks like something from NASA fell out of the sky – angry face, gaping air dams, and a pinched glasshouse widening impossibly over the wheels. The RS7's new look is proper space-age aggression.

Accelerating alongside it, I can see it squat heavily as it powers through the gears – good thing that hasn't changed then from the previous cars. The more we drive side-by-side, I notice the tiniest bit of roll in the RS7's body in the corners, while in the GT 4-door there's no give whatsoever, just immediate turn in and grip for days. I'm left wondering just how much better, or worse, the RS7 can be. 

Switching over to the Audi is like embracing a change in lifestyle, and philosophy. The minimalism is strong in here, with the straight planar surfaces covered in Alcantara, and bits of carbon fibre that look like they came straight from Audi Sport's GT works factory. Unlacquered, you can see and feel the carbon weave. Other RS-specific touches, as on the RS Q8 in this issue, include a skin for the infotainment, RS-specific dials and heads-up display and smatterings of the logo around the cabin. Though the seats are wider, and more comfortable, front and rear, it feels too serene; too regular sedan, after the pulse-racing drama of the GT 4-door. Usable, very much so. But clearly for someone who prefers a restrained aesthetic, a sharp contrast to its exteriors. 

Setting off though, my backside is already thanking me, as your chosen company for the ride will probably do too. Even though the RS7 rides on 22-inch wheels (the best modern wheel design out there right now), it feels like its riding on beanbags, which if you think about it, is pretty much what the air suspension is. There's the same unflappable serenity as the previous RS7 in the way it glides over the road, broken patches, expansion joints, potholes and all, even with the active dampers set to their most aggressive setting. The comfort is tangible, and you find yourself less on edge than in the GT 4-door. It may just be a false sense of security, you'd still have to watch out for your tyres but you feel more comfortable turning up the pace on a stretch of road you know well. 

And turn up the pace you'd want to. Similar to the AMG, under the hood is a 4-litre twin-turbo V8, with the turbos within the V for better response. A hallmark of this engine, the way it asks for cogs from the eight-speed torque convertor is as mind-blowing as I remember it to be. And, get this, it feels the tiniest bit more urgent now! The new-gen RS7 has lost some weight, a welcome by-product of moving to the VW Group's MLB Evo platform, so that's probably where it's coming from. Coupled with the distinct sense of the front lifting, pushing the wide rears into tarmac, the way the RS7 accelerates is more of a whole-body experience, even for the passengers. Especially since it feels more linear than the GT 4-door's visceral build-up of power through the revs. Linear doesn't mean boring though. Because 600PS and 800Nm feeling like it's poured out all at once makes for a relentless surge in g-forces. Like we saw in the RS Q8, the bottom six ratios feel really closely stacked, adding to the feeling that you're accelerating through one long wave of torque. 

Surprisingly, the little roll that's visible from outside the RS7 doesn't really feel like much when you're behind the wheel. In a way it actually helps when you're working up to a flow on a quick, twisty road. With the gentlest of body movements fore and aft, you get a sense of how the RS7 is responding to you. Which is necessary since the steering is, unfortunately, just a mild improvement over the previous RS7, though its eerily precise. A smidge too light for our liking, even in the RS mode, it's the only thing that leaves the slightest whisper of a doubt when you're really hustling. Because with a more neutral balance, the RS feels like it has the edge in mechanical grip over the GT 4-door, which feels a little more carefree and playful, occasionally stepping out to let you know when you're creeping up on the limits of adhesion. The RS7, as I found out after much trying, will only let go when you're being deliberately heavy-footed, coming more as a snap before the electronics snap back to get you on track. Both have all-wheel drive, but with the AMG being able to distribute more torque to the rear than the RS7's max of 85 per cent, it's natural. And that's without even putting the AMG into Race mode, which sends all power purely to the rear wheels. Gulp!

Smoky drifts with the family and friends in tow may sound like fun and games till someone gets green in the face, so we'd recommend sticking to the simpler joys in life that come with owning a super sedan in the first place. A quick drive made even quicker is often all that's needed to blow away the cobwebs, and therapeutic as it is, it's an experience that's best when it's shared.   

Photography by Anis Shaikh