With better straight-line performance, slightly better gas mileage, a roomier interior, and a more highly styled exterior, the Infiniti would appear to have beaten the Jaguar at its own game. And for many buyers, it has. But really keen drivers will want to read on, because this match isn't quite over yet.
While both our Jaguar and our Infiniti had driver-selectable modes that control throttle and transmission mapping, in neither of our test cars did those selections extend to the suspension (Jaguar does offer that capability but for the XFR only). That was fine with us, however, because we'd rather not have to switch back and forth between ride and handling; we always prefer a chassis that does everything well. In this case, that's what the Jaguar XF delivered.
It's perhaps not surprising that the Jaguar, with its nineteen-inch wheels, rides better than the Infiniti does with its twenty-inch footwear that is part of the M56's sport package, which also brings to bear a firmer suspension. The difference in ride quality between the two cars isn't dramatic, but the M56 gets knocked around a bit on patched, lumpy two-lanes, while the Jag is slightly more effective at taking the edge off sharper bumps.
We expected the M56 to make up the difference in cornering, but that wasn't the case. Both cars are tremendous athletes-a key component of their grand-touring personas. But while the M56 offers tons of grip and very quick responses, it also feels heavy and not particularly confidence-inspiring. We lay the blame for the latter on the four-wheel active steering (4WAS) -- a longtime Nissan fascination -- which is another component of the sport package. The 4WAS can steer the rear wheels in phase with the fronts, and you can actually feel it work, but the unnatural response makes for turn-in that's almost too aggressive. The 4WAS is also supposed to lighten steering efforts, but the M56 actually has a pleasing heft to its helm, although we did wish for more feedback.
The Jaguar's steering, by contrast, was a little too light, but that's about the only flaw in this cat's chassis. Even without the adaptive suspension or the active rear differential (again, both exclusive to the R), its movements are absolutely fluid, as the suspension seems to naturally transition from compliant to firm as it loads up. The car's response is very predictable, and it seems to be happier the harder you push it. The Jaguar feels much smaller than the Infiniti from the driver's seat, which is what you want when the road tightens up and the shoulder is ragged. Finally, if you want to get really enthusiastic, the Jaguar's stability control will let out some slack with its more lenient sport setting, but the Infiniti's electronic helper is either off or on, and when it's on it can be very intrusive.
With the new M56, Infiniti almost certainly was trying to build a BMW (after all, the 5-series and the Mercedes E-class are the big kahunas in this segment). But Infiniti ended up with a very good Jaguar-shapely, sporty, luxurious. In the end, though, the M56 Sport may just be trying too hard. In an M56 minus the sport package -- with its four-wheel active steering, sport suspension, and twenty-inch wheels -- the M's catalog of superiority would almost certainly put it over the top. But between these two cars, the XF proved to be the better Jaguar -- a sensualist's choice that stands in pleasing contrast to the German sport sedan's hegemony.