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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  M45: Great Machine - 2003 Infiniti M45
  By LoveCars - March 27 - 10:00 am

  This is a great automobile! The body style is unique and sharp. Although similar lines to the new Cadillac, I find the M45 lines much more refined compared to the "boxy" look of the Cadillac. The interior is very handsome looking. The automatic retracting seat and lifting steering wheel for ease of entrance and exit is a nice touch. The tiptronic 5 speed transmission lets me enjoy additional acceleration and control when I want to have extra "fun". The audio controls on the steering wheel make audio operation safe and easy while in motion. The voice controlled audio and climate control system also make for ease and safety of control while driving.

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  M45 vs 540i - 2004 Infiniti M45
  By bunny1 - March 24 - 10:00 am

  Just traded a BMW 540i for the M45. Beemer went into the shop one time too many. Slightly less than 540i in pure kick ass performance but a whole ton of very nice amenities that cost $1,000s more from BMW. Closest car I could find in overall performance to replace my 540i and reduce the maintence costs substantially.

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  Acceleration blocked - 2006 Infiniti M45
  By Bob Ringgenberrg - March 23 - 11:13 pm

  Rarely when attempting to accelerate for a stop or slow speed, it gets stuck at 2,000 rpm and 20 mph and will not advance . You must take your foot off the accelerator and reapply slowly, Same with the manual mode. Can be dangerus when changing lanes in heavy traffic. To dealer 3 timers, they say they can not replicate this and it is fine. It is not fine, did this from day one. Some one said a software problem may exist as it is 1st generation software. I think I will trade in on a G35. I really like the M45 but but every time you want to get up and go you hold your breath because there is a chance it wont. Any help appreciated.

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  Always liked the style and power. - 2003 Infiniti M45
  By realdeal305 - March 6 - 5:14 pm

  I just purchased a 2003 M45 with 70,000 miles on it. Ive always liked the style and the power is great. Its a great used car bargain Im just glad I never bought it new. The quality is below luxury in my book. I also have a Lexus the quality of the material and finish is top notch. The Infiniti not so much trunk struts dont work, center arm rest is cheap and feels loose, sunroof liner coming apart, fuel guage not reading correctly (recalled ), engine doesnt start up on first try sometimes, and airbag light is on. Alot of issues for a car with 70k, but Ive always wanted one and I dont regret buying it for $7500. Especially since its not a daily driver. I have a Gs300 and Yaris for that.

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  FANTASTIC II - 2007 Infiniti M45
  By CSRMAX - March 4 - 5:00 am

  Excellent... upgraded from a a early (March 2005) M35 Sport.

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  Amazing Ride - 2007 Infiniti M45
  By Kris Shanahan - February 27 - 4:40 pm

  This car continues to blow my mind. It is by far the best car I have ever driven. I trade in every 2-3 years, but it is going to be hard to give this car up.

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  Love this car - 2007 Infiniti M45
  By Kevin - February 21 - 2:56 pm

  Ive had the M45 for 2 months. Ive driven it almost 4500 miles and I love the car. Havent had even one small problem.

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  I am another satisfied customer - 2008 Infiniti M45
  By alxpush - February 20 - 4:36 pm

  I am at the end of my 39 mo lease (bought 2006 model on 10/30/05), love the car from day one. Perfectly comfortable inside and outside. Excellent nav system, very useful rear view camera (day or night), especially for parking in tight places, plenty of power. Overall 9/10, only because I know, there is better cars out there which I have not tried yet.

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  Horse power and torque is incredible! - 2006 Infiniti M45
  By LeonC626 - February 18 - 12:30 pm

  I originally had my sights on the QX56 but after test driving the M35 and M45, I decided to go with something sporty. The initial test drive with M35 wasnt quite satisfying, so I decided to test out the M45. The V8 on the 45 version has a great compromise on the bulkiness of the sedan. The car takes off like a rocket. The thrill on speed is just one of the best features, the stability is probably the second biggest accomplishment for this car. Body roll is minimal when serving through the lanes in high speed on the freeway. The manual shifting is precise and quick. The only recommendation I have for this car is a six-speed auto gear box insteaf of five and a small lift on the rear facia.

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  Fun Summer Ride look out for snow - 2004 Infiniti M45
  By wcosmo - January 29 - 7:23 am

  poor in snow!!!!!!!!!!!!!! outstanding dry road conditions, fun to drive voice control not used after second week