Infiniti's 5-series rival used to be a nice, but anonymous car. After hooning it through Southern California's canyons, that's no longer the case. Now, the is Japan's Jaguar.

Full Disclosure: Infiniti wanted us to drive the new M so badly they flew us out to San Diego, put us up in a fancy hotel and hired one of GQ's top ten sommeliers to serve us fancy wine. I thought the Viognier was pretty acidic and wasn't terribly impressed with the Pinot Noir either. Maybe you shouldn't believe everything you read in magazines.

Nissan's luxury brand has always been a second rate player in some of the most competitive vehicle classes in the world. They want to be BMW, but basing cars on the front-wheel drive Maxima platforms was never going to get them there. Then, starting with the 2009 G37 Sedan and more recently the Coupe and , Infiniti suddenly became competitive. You don't need to make excuses for Infiniti's latest generation of cars.

Fat people in shorts, missile testing, horse farms and fake tans. That pretty much sums up the 2009

And you definitely don't need to make excuses for the new M. The V6-engined is more powerful, lighter and cheaper than either the 2011 BMW 535i or the 2010 Mercedes E350. The 5.6-liter naturally aspirated V8 in the makes 420bhp and 417 Lb-Ft and weighs 4,028 Lbs. Compare that to the twin-turbo 2011 BMW 550i and its 407 HP, 442 Lb-Ft and 4,200 Lbs.

It's actually the lighter that we prefer driving. You can feel that it's 170 Lbs lighter in the nose, leading to greater agility and lighter steering. Both the 37S and 56S are fitted with an active rear-wheel steering system that can turn the rear wheels into a corner by up to one degree. In action, it settles the rear as the car steers into a corner, which allows the car to steer faster. This isn't just an on-paper gimmick either, you can feel the rear tucking itself in as you steer aggressively into a corner. It turns like a car half its size.

The Sport package (the "S" after the numbers) adds $3,650 to the base models (M37 = $46,250, M56 = $57,550), but brings with it 20-inch wheels; summer performance tires; lower, stiffer suspension; a more aggressive-looking front fascia; more heavily bolstered seats and paddle shifters for the 7-speed auto.

The lack of a manual option makes the M37S sound less like a car for enthusiasts than the 5-series, but the torque converter works so ridiculously well in manual mode and is so smooth when you let if shift gears itself that we actually prefer it to most automated manuals. The downshift rev matching means you can rev it to the limiter when slowing down for a corner and upshifts are fired off the split second you request them when accelerating out.

Infiniti's added a drive mode selector complete with an "Eco" button to the M. All the Eco does is remove all pretensions of throttle response, making the car feel dangerously slow away from the lights unless you floor it. In practice, you'll just want to leave the car in "Sport" mode, which doesn't diminish smoothness, but makes the auto mode more willing to kick down and hold gears, actuates the rear-wheel steering more aggressively and, if you've spec'd the $3,000 "Technology" package, also tweaks something Infiniti is calling Active Trace Control, which is sort of automatic trail braking that should help drivers that enter a decreasing radius corner too quickly actually make it around without killing themselves.

Active Trace Control tops the list of whizz-bang techno features available on the M. There's also Blind Spot Intervention, Double-piston shock absorbers and Distance Control Assist along with the list of now-common technologies like radar cruise control and active noise cancellation that you'll find on most competitive luxury sedans.

Blind Spot Intervention works in conjunction with the Blind Spot Warning and Lane Departure Prevention systems, grabbing the brakes on the opposite side if you steer into an adjacent lane while a car is in your blind spot. The effect is that you're steered quickly back into your own lane unless you override it by adding more steering. Don't worry, you can still ram other cars on the highway if you really want to.

The Double-piston shock absorbers use a piston inside another piston to alter the rate of oil flow in the shocks to deal with high frequency vibration. Travel along a concrete highway, for instance, and the shocks become initially softer to reduce the impact of the expansion joints. Even the Sport models ride exceptionally well, but still have great steering feel.

Distance Control Assist is sort of like radar-assisted cruise control. It monitors the distance between you and the cars in front; lift off the gas when you're a bit close and it'll slow you down a bit to maintain a safe following distance. The effect is only noticeable if you're looking for it, but should help distracted drivers be a little less accident prone. Unlike cruise control, it's always on if you want it to be.

Unlike some other automakers, Infiniti realized that a lot of drivers don't want their cars to drive for them. All of the intervention features are in the "off" position normally, only turning on if you ask them to. Thank you Infiniti for giving us the option of using them without the hassle of turning off 10 things every time we get in the car.

One thing you will have to turn off is the lane departure warning, which beeps loudly every time you drift out of your lane. Like its competition, the Infiniti M is now a huge car (72.6 inches wide and 194.7 inches long) and while it drives much smaller, you'll have to cross the center line a lot if you really want to hustle it down a back road. The loud beeping of the lane thingy is seriously annoying.

Inside, there's also an utterly unnecessary piece of technology called "Forest Air" that can vary the speed of air through the HVAC system to make it feel kinda like a breeze. It's unnoticeable unless you hold your hand in front of one of the vents, but spoiled drivers will appreciate the system's ability to identify and remove or filter out bad smells as well as allergens and dust.

Getting back to the M37S, it's powered by the same 330 HP, 270 Lb-Ft, 3.7-liter V6 that's in the 3-series-sized G37. We were worried that it'd make the heavier M feel sluggish, but it does anything but. The urgent revs make traveling at a given speed feel more urgent than the big V8, the progress of which is so smooth that it's hard to feel the added performance. Using the paddle shifters, working the 3.7 hard is a lot of fun, enabling you to exploit the communicative, capable chassis. Doing the same thing in the V8 is probably faster, but feels more stately and relaxed. We'd go for the 3.7 since we enjoy going around corners, but people planning long trips or lots of boring commuting might like the ease of the 5.6 a bit better.

Also like most of its competitors, adding all-wheel drive to the normally rear-wheel drive car completely screws the whole thing up. Not only does it add about 200 Lbs and reduce the fuel economy a smidge, it also removes all steering feel and makes the M feel heavier and more sluggish. If you're one of those ill-informed people that think you need AWD just because it snows where you live, you need to take it from us: winter tires, not AWD make your car snow-capable. Don't ruin the M, keep it RWD and buy a set of winters, then store them in your garage during the summer.

Infiniti has seriously upped its game inside the M, continuing the exterior's up-market Japanese theme inside with Ash, metal accents and nice plastics. We love seeing a Japanese company finally embracing its Japanese-ness, unashamedly presenting compound curves, flowing shapes and intricately-stitched leather instead of the usual teutonic restraint. Check out the heavily knurled speedo and tach for an example of how well this can work.

Bizarrely, the rear leg room (36.2 inches) has been reduced by one inch over the outgoing model, meaning the back seat is 5-series tight instead of E-class spacious. The trunk, conversely, is huge. I offered to climb in for photos, but since we were parked less than a 1/4 mile from a border checkpoint and Mexican-hunting agents were swarming the roads, we figured doing so might be a bad idea. One upside of border guards: they don't pull you over when they see you overtaking a truck at close to 100 MPH around a corner, well, at least not if you're a gringo.

So Infiniti's created a luxurious four-door that looks gorgeous, goes fast and doesn't have much space in the back. But unlike the Jaguar XF, we think the M is going to prove fully competitive with the German master race of luxury sedans. While we won't know for certain until we've had the chance to drive all three back to back, our initial impression is that the M offers a much sportier drive and is much faster than the E-class, sacrificing interior space in the process. We're guessing it's going to be as fast as the 2011 535i and 550i and, with that rear-wheel steering, might even have the edge on handling. Infiniti suddenly has our attention.