We'd like to pretend this super-sedan comparison test came together as the result of months of careful planning but, in all honesty, the three cars sort of fell into our laps. As the latest and greatest sports saloons from each company, they represent the best way to get four people to your destination at high speed and in great comfort. And with all being available at once, it seemed rude not to test them together, especially since each is knocking on the door of $100,000, so very few corners have been cut in the process of creating some of the finest autobahn stormers the world has yet seen.

While each car would be comfortable on the race track, we decided to again conduct our comparison on public roads, covering more than 400 miles in our quest to answer the lingering question: which was our favorite super-sedan?

Our ultimate destination was the barren, wide-open spaces of Death Valley, NV, but we never made it. Instead, we diverted into a mountainous region to the south-east and discovered deserted roads that served as our testing grounds.

If we had one regret, it's that we failed to include the BMW M5. It's still the benchmark in this category and would have established where these newcomers stood in terms of the M5's performance and ability.

That said, we tested our modified Project Jaguar XFR against the M5 in EC 11/13 and found the two compared very closely, so we hoped the factory hot rod XFR-S would be the equal of the M5.

The test would see the return of Ezekiel Wheeler, our recently departed colleague, who made a guest appearance as vehicle tester/wheel cleaner/light holder, and his presence was greatly appreciated. As was our video tech Gary Cogis, who would also help with driving duties.

To Begin

We'd start by escaping LA at 5am, attempting to circumvent the snarling traffic that clogs the city's arteries. But even at this hour, the traffic was heavy and relatively slow. However, our transport would allow us to capitalize on any gaps that appeared and hit the road running.

For once, there wasn't a wrestle for the keys. There was no short straw since each was able to stand proudly on its own merits. And while opinions among the team were already starting to form, I was beginning to spot a flaw in an otherwise perfect plan - how were we going to separate these cars?

Let's start with price, since it's a key factor. At retail money, the limited edition Jaguar was the cheapest, starting at $99000, although our car would be bumped up to $105770 as tested thanks to its heated windshield, carbon engine cover, carbon rear wing ($3500!) and delivery.

Very close behind was the Mercedes-Benz E63 AMG S at $99700, which jumped to $106825 thanks to its Designo black lacquer trim, 19" black AMG wheels, red nappa leather, Driver Assistance package and delivery.

We should also point out this S model had an extra 25hp and 60 lb-ft among its arsenal, giving it an advantage over the opposition.

The most expensive of the trio by quite a margin was the $104900 Audi RS7, which hit a dizzying $122545 thanks to pearl paint, B&O stereo, heads-up and night-vision assist, Driver Asssitance, wood/aluminum interior trim, sports exhaust, 21" wheels with summer tires, matte aluminum exterior trim, soft-closing doors and delivery.

So right away, we had a pecking order but it would be turned on its head by our first judging criteria, that of the overall appearance...

Style

No doubt helped by its grey pearl paint, matte trim and oversized wheels, the RS7 was selected as the most attractive by Alex and I. Its elegant grille and discreet, deployable rear wing further enhanced the four-door coupe's visual appeal, reinforcing the position of Audi's designers as among the best in the business right now.

Alex initially chose the Mercedes because he liked its simplicity, but was eventually won over by the Audi. Ezekiel chose the XFR-S for its design concept and, while we all loved the black-framed grille, I couldn't forgive its '90s side skirts and boy racer wing. Compared to our Project XFR fitted with carbon fiber Vorsteiner spoilers, the factory effort looked somewhat juvenile for such an expensive package.

The Benz didn't garner much of an emotional response. It's a handsome car with some nice lines and is clearly an improvement over the outgoing model. The front spoiler and rear diffuser had some nice detailing, but the team didn't appreciate the black wheels, although I didn't see the problem...

And while we're on the subject of Audi dominance, the best interior vote unanimously went to the RS7. Its combination of luxury, ergonomics and design detail won full approval.

Like all three cars, it had great sports seats, providing phenomenal support, only surpassed by the AMG that offered active bolster movement. These would move on one side as you cornered, increasing their support and keeping you in place. They weren't like the early versions of this technology seen in the previous BMW M5, which used to be a little abrupt. The movement was gentle but sufficient for the task.

In fact, the Mercedes interior took second place and might have won but for its button rash, which swum against the current trend for minimizing control surfaces. It will undoubtedly find its fans, and it did everything the Audi did, just with a more confusing array of switches and buttons.

The finish in all three cars was exemplary, with the two Germans showing the vast resources available to the parent companies for the latest technology and interfaces. I was particularly taken by the Audi's black wood trim with pin-stripe aluminum inserts that brought a nice touch of class and elegance.

The Jaguar wasn't far behind but its beautifully crafted leather surfaces were let down by some cheaper plastics. Under ordinary circumstances, you wouldn't notice these deficiencies since the overall finish was superb, but stacked against the might of Germany, it was slightly under par.

So right away we had the Audi at the bottom of the first criteria but at the top of the next two. It was going to be a bumpy ride.

Performance

As we said, there were no lemons in this basket, and we could each live with any of the three cars in terms of appearance and interior function. So what remained was the most important assessment of all: the performance. And when the least powerful car in the group boasted 550hp, it was going to be a fun day.

Using the freeways to escape the city, each car was totally in its element. They made such light work of high-speed travel that you had to keep a constant eye on the speedo as you poked the gas pedal to pass slower traffic. Hitting triple-digit speeds was ridiculously easy, especially when the Jag and Audi grilles seemed to move early morning traffic from our path.

Each car had adjustable suspension, so you could dial in the comfort setting to iron out the expansion joints on concrete roadways, or switch back to sport when the opportunity arose.

Perhaps their collective weakness was a healthy thirst. The Jag and Merc claimed a combined consumption of 18mpg, with the heavier Audi boasting 19mpg, but we found ourselves filling up sooner than the numbers would suggest. In fact, we were slightly alarmed at how quickly we drained the tanks in the mountains.

Under normal driving conditions, each was able to better its combined number, with the Audi returning the best consumption thanks to its cylinder deactivation feature.

Yet with a surfeit of power, great handling, powerful brakes and extensive infotainment, there was nothing to really separate the three cars on the freeway. In fact, there were times when it was only the position of the switchgear that reminded you which car you were driving.

That would change once we exited the interstate and hit some turns. Again, the adjustable suspension systems came into their own, and this time we noticed the steering gained weight, helping to guide the cars with more precision. In sport mode, the throttle activation also became more sensitive, allowing you to modulate the acceleration on corner exit.

Not that the Audi or Mercedes needed much delicacy. With their standard quattro and 4Matic systems, you simply buried the throttle and let the electronics deal with the subsequent traction issues. The programming was so proficient we never experienced any shortage of grip, even on broken surfaces or with gravel underfoot.

In this environment, the AMG rose to the occasion most obviously, possessing the kind of mid-corner grip you wouldn't normally associate with a 4276 lb sedan, especially an E63.

In the past, the RWD E63 models were somewhat unruly, allowing wheelspin and oversteer to dominate proceedings. However, the 4Matic system has utterly altered the car's personality.

It's now all about stringing together perfect apexes and exiting a corner at maximum velocity. Behind the wheel, it was difficult to remind yourself this was a very large, very heavy, 577hp executive sedan because it was performing like a nimble sport compact.

The RS7 seemed to adapt less proficiently to the twisty roads. Its serenity and poise on the freeway gave it a slight advantage in that environment, but once the going got tough, the Audi struggled against the competition.

That's not to say it was incapable or unruly. It certainly wasn't embarrassed in the company, it simply wasn't as overtly sporting.

The Mercedes reminded us of the Corvette Stingray Z51 we tested last month against the Jaguar F-Type V8S. Its controls seemed to similarly gain weight and substance as it found speed. Both cars were also more inclined to roll into the turns, giving you a better impression of speed and traction. Whereas the Audi's steering remained relatively light in its sport setting and the body slightly over-damped.

At more sane speeds, the Audi RS7 seemingly wafted you along on a carpet of feathers, but pushed up some mountain roads, those feathers were less useful.

Again, it wasn't a dog. The Audi could be pushed hard. The sports exhaust on the 4.0L V8 was bellowing, the quattro system finding prodigious grip, but it simply didn't have the precision or brutality of the Benz. Most people under most circumstances would never know this since it's a massively capable cruiser, but it isn't in the AMG's canyon carving league. It's maybe 5% less capable but, if that's your main criteria, it's good to know where they stand.

Lined up against these grip monsters was the Jaguar and, to be honest, at this point we'd almost discounted it from the reckoning. Its 550hp supercharged 5.0L V8 was marginally the least powerful and, while it had plenty of low-end grunt, it ran out of steam at the top-end where the biturbo motors were still pulling hard.

It was also the only RWD platform and initially seemed to lack finesse. In its Dynamic mode, the loose road surface was catching out the rear wheels, causing it to oversteer more often, losing ground on the grippier Germans.

Its blown V8 was also disappointingly muted. After driving the Jaguar F-Type and XKR-S, we were expecting the new XFR-S to roar like a big cat, but it lacked the exotic soundtrack of its stablemates.

When leaving the mountain I jumped back into the Jag and decided to give it another chance. Heavier than the Mercedes but with rather numb steering, we built up speed as the other two cars disappeared around a couple of corners. Stowing bags and equipment, it took us a while to settle before setting off to close the gap.

To my astonishment, it took no time to reel in the two Germans. Admittedly, it required a slightly different approach on my part; lugging from low revs to utilize the supercharged torque and changing gear early on the paddles to avoid the breathless top-end. Driven this way, the XFR-S was starting to make sense.

The adaptive suspension was dealing superbly with road imperfections, keeping its 20" forged wheels nailed down and allowing the fat tires to do their job. The brakes were easily as capable as the flashier alternatives on the opposition, although they did appear to be the hottest at the end of our adventure.

The XFR-S was totally deceptive. It didn't feel as though you were driving it quickly, but without really trying, we caught the Audi and Benz that were clearly using all their acceleration and grip to leave the mountain.

With 0-60mph in 4.4sec, the Jaguar was the slowest of the group by a considerable margin, despite the advantage of an eight-speed transmission. The XFR-S was embarrassed by the 3.6sec AMG and 3.7sec RS7, yet up in the mountains, where it really mattered, the Jag had the right stuff to hold its own.

After swapping back into the AMG and being followed by the Jaguar, I was asked whether I'd been trying to stay ahead. I didn't want to admit I was pushing the E63 hard because I could see how easily the Jag was keeping pace...

As our journey continued, the Brit continued to perform its magic trick: covering ground without seeming to expend any effort. As several drivers observed, the XFR-S appeared to shrink around you, feeling more like a sports car than either of its rivals.

It was an impressive party piece but somehow the Jag lacked the engaging personality of the Merc, which made you feel more involved despite its lack of drama. The Jaguar was certainly an enigma.

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