Rain, on racing circuits, it's considered one of the great equalisers,
but for road-going performance cars, rain is, well, a bit of a wet towel. But today,
I plan to use precipitation to my advantage. Here we have two genuine,
all-weather performance cars in the Audi RS7 Sportback and the Mercedes AMG E 63 S,
and we're at a very wet, very greasy, Wakefield Park circuit in Goulburn to see which is best.
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Ordinarily, these conditions would be considered a no-go zone for four-door super cars,
and let's be honest, that's exactly what these two are. The E 63 follows a family of E-class
vehicles, dating back to the original hammer of the 1980s while the RS7 sits at the pointy
end of Audi's horsepower rankings. Both have been updated in recent months and are all-wheel drive,
and output about 600 horsepower in the old money. Although they compete for similar buyers,
there are some noticeable differences. The E 63 is a traditional sedan while the RS7 Sportback
has a more design-oriented profile, underlined by its coupe-like lift-back rear. The Audi is also
significantly cheaper at $224,000, compared with a touch over $250,000 for the AMG. For the record,
we also requested the updated BMW M5 competition for this test, but they were none on fleet.
This pair took on more common ground in 2017 when the E 63 moved to an all-wheel drive layout. Now,
although the move was initially met with some scepticism, the general consensus was that
all-pull grip was a great way of harnessing this car's twin-turbo V8 engine. For 2021,
AMG engineers have revisited the internals of the E 63, but it wasn't the engine they were worried
about. Instead, AMG engineers have quietly replaced the subframe bearings and bushings,
re-calibrated its active engine mounts, replaced the tie rod bearings and retuned the software
responsible for the active dampers. The AMG's three-chamber air springs are said to share
the same spring rates or stiffness as before. The AMG marginally betters the Audi in terms of
outputs with an additional 9 kilowatts and 50 Newton-metres from its 4.0-litre displacement.
In the all-important nought to 100 dash, the Merc wins it by a nose as well,
3.4 seconds versus 3.6 seconds claimed. The speed here is raw and scintillating,
not that you'd really expect it from the E 63's decidedly executive body.
Smart and understated, that sounds like the key character trade of any performance Audi
for the past 15 years. However, the 2021 Audi RS7 Sportback is no shrinking violet.
It has a decidedly more extroverted appearance with bulbous guards,
huge 22-inch wheels and more styling changes inside and out. It's not all just cosmetics,
though. The engine has been augmented by a new 48-volt mild hybrid system,
and it has 50 Newton-metres more torque than before, just shy of the AMG. Adaptive
air suspension has also been added while an RS7 sports exhaust and 22-inch Audi sport alloy wheels
are standard now as well. Stopping power comes from large 10-piston callipers up front,
gripping huge 420 millimetre front discs and 370 millimetre rear discs, bigger than the AMG
on both counts. However, the latter was optioned with carbon-ceramic brakes on test. Conditions on
this day are tricky, so we've enlisted the help of Tim Brook, a champion in Toyota's competitive
86 racing series and a current front-runner in the V8-powered Australian Trans-Am category.
We'll get our star racer's thoughts in a moment, but first, it's time to try and tame the RS7.
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Now, these two cars, it is definitely the RS7 Sportback
that feels the more confidence-inspiring on a circuit. Granted, they're both all-wheel drive.
Granted they both have 4.0-litre, twin-turbo V8s, outputting around 450 kilowatts, but
it's the way that the RS7 goes about its business on the circuit. It feels
the more connected to the road, and in wet conditions, it feels more tied down as well.
The RS7's user-friendly traits are augmented by its all-wheel drive system, which feels
less susceptible to switching ends over standing water. Although the same Pirelli P ZERO tyres have
been shod to both vehicles, a slightly different tread block lends the RS7 another small advantage.
In this test, it really does feel like the more confidence-inspiring choice. There's a
little bit more roll on turning with the RS7, but that rear-steer system does mean that it feels
really quite well tied-down at high speeds. It turns in nice and consistently,
and if feels very natural and organic, which is a really important element. It really feels safe,
sure-footed on a race track, wet or dry. Of these two vehicles, this is probably the car that I felt
more comfortable in, faster. In the hands of our resident racer the RS7 feels more
manageable and stable in the conditions as well, with shorter braking distances
and more advanced driver electronic aids, at least in the wet. That brings us to the AMG.
[pause]
Now, these two cars, the E 63 feels like the quintessential
German hot rod. That is the hallmark of the AMG nameplate, and really does stand strongly
in this car. It is a brute of a thing. It's tail happy. It's muscular. It's got a great soundtrack,
but it can be a little bit intimidating, at least initially on a green wet track. The E 63 is a car
that really I should just grab it by the scruff of the neck and take control, and when you do that,
it is quite a willing accomplice, even on a really wet circuit. Of these two cars,
it doesn't feel as well tied-down, the electronics kind of nip at the wheels rather than intervene in
a really linear fashion like the RS7. And I'll be honest, initially it felt really intimidating
especially when it was flogging down with rain, but you start to get used to it a bit more,
and you really do feel the rear-drive attributes of the E 63. I'd argue, it's probably not as quick
as the RS7 on a wet circuit, but you're gonna be having a lot more fun behind the wheel of the AMG.
Although it is hard to exploit pure horsepower in these conditions, the AMG wins it for outright
punch and muscle. The tunability of the E 63 is another clear strength in this comparison,
in the form of three-stage air suspension, more drivetrain and chassis adjustability.
It speaks to the fact the E 63 is the more track-focused of these two. Even
with a slightly muted exhaust note for 2021, it is certainly the more extroverted offering,
and once you come to grips with its power and attitude, it is highly entertaining as well.
Tim noted the AMG's electronics felt more intrusive and that its narrower
front tyre may have impacted turning response and balance. When he stuck to the racing line,
Tim said you had to work harder in the AMG, but when you did, it would be a lot more fun.
Away from the circuit, the RS7 gets the nod in terms of road comfort with a more compliant ride,
less road noise and more refinement. The RS7 also wins points for its low-speed manoeuvrability,
thanks to its rear-wheel steer system. The AMG's
drivetrain is subject to some binding during tight low-speed cornering,
but the gear box is noticeably smoother than the Audi's during curb-side departures.
The interiors here are both first class, the Audi with lots of aluminium trimmings,
faux carbon fibre highlights and lashings of Alcantara suede.
Dual screens in the centre fascia effectively divide climate control and other vehicle settings
from the infotainment while the digital instrument cluster is clear and concise
in its readouts. The Audi's liftback style rear is a clear winner for boot space. However, its design
does impose more compromise in terms of rear-seat space and toe room. Over in the Merc's corner,
the interior has a greater focus on dynamics with deeper bolsted front chairs and go-fast cues.
There's a new steering wheel with capacity of touch controls plus reworked touch screens with
camera-based augmented reality SatNav, combining digital graphics with a live video feed of the
road ahead. On the maintenance front, the AMG trumps the Audi with a more generous warranty,
five years unlimited kilometres versus three years unlimited kilometres. However,
the Audi is almost half the price to service over a five-year plan, at $3910, compared
with the staggering $7000 for the AMG. Now you might rightly question why we choose to take two
quarter-of-a-million-dollar luxury cars to a circuit, but I think today, the RS7
and the E 63 have both shown that the electronics and driver aids in these modern 600-horsepower
cars are so good that you simply can't exploit them on a public road. Both have been really
impressive and are genuine all-weather cars. But for me, it's the Audi RS7 that takes it by a nose.