Overview & Reviews

Though high-end vehicles now come in more shapes and sizes than ever, the midsize luxury sedan segment remains the heart of the luxury automobile market. Nissan's luxury division, Infiniti, has been around since 1990, yet it had no real presence in this key segment until 2003, when the V8-powered, rear-wheel-drive M45 was launched. Although it offered a credible amount of luxury and performance, the original M45's relatively uninspired design and cramped interior kept it from registering anything more than a faint blip on luxury buyers' radar screens.

The last iteration of the Infiniti M45, however, enjoyed wide critical acclaim. With substantially more space, a tremendous amount of technology and comfort features, and a bold, imposing exterior design, the last M45 was a high-tech powerhouse with plenty to offer midsize luxury car shoppers. Its performance capabilities were raised significantly due to things like available four-wheel steering, a precisely tuned suspension and strong brakes. Even though the V6-powered M35 represented a significantly better value and offered potent performance, the current M45 was a swift, stylish, superbly executed luxury sedan that should be considered with the contemporary top players in the segment.

The M45 was replaced by the redesigned M56 for the 2011 model year.

Most Recent Infiniti M45

The most recent generation of the Infiniti M45 was produced from 2006 to 2010. First-year models were listed as having 335 horsepower, with subsequent models rated at 325 hp. This was due to a change in horsepower measurement rather than actual output and thus, performance was unaffected. The M45's five-speed automatic transmission had manual-shift control and a sporty rev-matching feature that imparted a particularly lively feel to downshifts.

Originally, there were two trim levels: base and Sport. Even the base car included such items as leather upholstery, driver memory functions and dual-zone automatic climate control. Stepping up to the Sport netted you 19-inch wheels, a sport-tuned suspension, active rear steering and adaptive xenon headlights. Options included such high-tech fare as navigation adaptive cruise control, lane-departure warning system and a surround sound system.

For '08, the mildly face-lifted M45 gained the option of all-wheel drive and its M45x AWD trim level. The Sport trim was also replaced that year in favor of an optional Sport package on rear-drive base models, while the navigation system was given a welcome overhaul that included a hard drive and digital music storage. It remained unchanged before making way for the redesigned M56.

The Infiniti M45's interior was well appointed and well built, with firm seats that were highly adjustable, comfortable and heavily bolstered. However, the competition in this segment was pretty intense and the M35 wasn't quite as elegant and thoughtfully engineered as some of its rivals. The quality of materials was a bit uneven, and we found that the layout of the center stack controls wasn't as clean and intuitive as it could be.

In road test reviews, editors praised the Infiniti M45 for its explosive power, sharp handling and its bounty of luxury features. Criticisms of the M45 included overly intrusive road noise and complicated center-stack controls that were hard to master. Also, we questioned the logic of buying the thirstier V8, when the M35's V6 provided nearly as much power.

Past Infiniti M45 models

The first-generation Infiniti M45 was sold for 2003 and '04 -- there was no 2005 model -- and was basically a Japanese-market Nissan Cedric luxury sedan brought over to fill the gap between Infiniti's near-luxury G35 and the larger, technology-laden Q45. Engineered for the narrow streets of Japan, the M45's cabin proved too narrow to hold corn-fed Americans comfortably, and the backseat was scant on legroom for a car of its size. Even worse, the M's exterior design was bland to a fault.

However, it was fast. The original M45 was available only with a 340-hp V8 and rear-wheel drive. Combined with big 18-inch wheels and performance tires, the M45 delivered respectable handling. Equally important, the original M45 was equipped with nearly the same number of safety features as today's model.

Cheaply priced and available with most of the luxury features found on the larger Q45, first-generation M45s generally represent strong used-car values in terms of feature content and performance. For shoppers who like the car's combination of stealthy speed and luxury, and don't need a lot in the way of interior room, the first-generation Infiniti M45 could be a good match.

User Reviews:

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  Sport M45 Surround Sound - 2006 Infiniti M45
  By Mitsman - June 30 - 2:40 am

  If you like music, you have to get the Dolby 5.1 Surround Sound w/ DVD Set Up. The absolute highest fidelity Sound EVER experianced. You will need quality Live Music Videos and be sure to choose the Dobly 5.1 "Audio Option" on the DVD. Absolutely unbeleivable. And obviously, this car is extremely nice in every area I could write about.

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  Outstanding Sport Sedan-Best for the US! - 2007 Infiniti M45
  By Dave - June 10 - 7:43 am

  I test drove BMW 335i and xi, 328xi, and 535i and xi, and although these cars were more aggressive drivers cars than the M45 sport sedan, I purchased the Infiniti. Major deciding points: M45 was priced similarly to the 335xi, but had more power, better features, and much better interior than any of the BMWs. If I were driving in Europe, I would buy the BMW, but in the US, the M45 Sport is a better package and it is cheaper!! By the way, the 328xi and 530xi do not even compete with the M35, let alone the M45. If you are seriously considering any version of the 2007 328 or 2008 530, do yourself a favor and compare it to the M35/45. Infiniti clearly beats these cars!

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  Best car ever owned. - 2008 Infiniti M45
  By Joe Warner - May 16 - 1:50 am

  The 2008 M45x is one of the most luxurious and best handling sedans in this category. It may not be the best in every category but the combination of luxury, performance and features is excellent.

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  M35 - Great Car for Non-Soccer Phase - 2007 Infiniti M45
  By fagnaml - April 29 - 9:06 am

  We purchased an M35 for our new "non-soccer parents" phase of our life (were in our late 40s). After ~6 weeks of driving we are extremely pleased with the comfort and performance (not surprising considering our last vehicle was a Toyota Sienna minivan). The disappointment is the mileage is at the low end of its rating (were getting ~20 mpg when gas is >$3/gallon!). We test drove the Lexus GS 350, Mercedes E350 and Acura RL. The M has the comfort and peformance we wanted.

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  The Only One - 2003 Infiniti M45
  By cosmicm - April 11 - 10:00 am

  If you want quality, luxury, performance -- without owning the same car as every other joe on the highway - - this is a simple choice. Infiniti of Cincinnati is offering them for as little as $399 on a 39 month lease -- and nothing out there can touch that. Almost everyone that sees my car loves it (Graphite on Graphite with chromes). Most people think it is a Mercedes or Bentley. If you are at all considering a BMW 5- Series, Lexus G Series, Audi A6 or Mercedes -- you owe yourself an M45 test drive.

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  Dont buy it. - 2003 Infiniti M45
  By davec160 - April 7 - 7:55 am

  Obviously all used cars now and if you see one on the lot steer clear and let it rot on the lot. We have owned one now for about 4 years and up til recently have been some what satisfied. It has about 80K on it and everything is falling apart. Like previous poster gas guage is unreliable and it has been in the shop waiting for a part for over a week now. The whole instrument cluster has to be replaced!! A big rig has a tighter turning radius. Interior lights have been replaced a few times too and rarely work correctly. Infinities are not built to last.

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  2003 INFINITY M45 - 2003 Infiniti M45
  By SCHULTZ - March 18 - 10:00 am

  THE VEHICLE IS FUN TO DRIVE. THERE IS NO WIND NOISE, IT CORNERS WELL. I HAVE NOT HAD TO HAVE ANY REPAIRS MADE TO THIS DATE. I WOULD LIKE FOR IT TO HAVE MORE REAR LEG ROOM. ALSO THE TRANSMISSION SHOULD SHIFT MORE POSITIVLEY.

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  Good solid vehicle - 2008 Infiniti M45
  By MTCS - February 16 - 9:13 am

  I traded in a 2009 Maxima for the 2008 M45X (new). This is a very nice luxury vehicle. It has all the toys inside that the BMW 5 series has. The smart cruise control is awesome. This vehicle accelerates very quick. This car is a keeper. It is not a head turner. I think the goodies inside with all the electronic gadgets you get to play with is where you get your monies worth out of 2008 M45X. The surround sound is awesome. Pretty quiet ride, not as smooth on rough roads as I was expecting. On the highway you cannot tell the difference between 75 and 90 mph. Simply a well built machine. I had buyers remorse initially but the car has won me over, this car is a keeper!

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  Infiniti Does it Again!!! - 2006 Infiniti M45
  By Daniel - February 4 - 8:06 pm

  I just received my new M45 with the Premium Package, and I have to say it should be called the everything but the kitchen sink package! I have a 2004 FX45 that I love, but this M took my love for Infiniti to a whole new level. There is not a car out there in its class that can compete with all the first rate technology they use in this vehicle. You name it, it has it, and if it doesnt have it, you probably wont find it anywhere else either. Power, tech, comfort, convienece, looks, and a beautiful interior should be making all the other Makers questioning their line ups. I used to be a Acura lover, then Lexus, even BMW, but it looks to me that Infiniti has won me over. Couldnt be happier!

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  HOLD ON TO YOUR HAT! - 2004 Infiniti M45
  By miamiandy - February 4 - 10:00 am

  With a 340 HP engine that it shares with the Q and many other features also shared with the Q 45 make this the sleeper of the under 50K bracket. You will not believe the acceleration and handling on the open road. The control panel takes a little learning and the sound system is mediocre. I LOVE the body styling and think it will become a novelty because of its 2 year production cycle before a SAAB like restyling. Ill stay with my 2003 M45 style.