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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  Really is the Muscle Car with Brains!! - 2003 Infiniti M45
  By Daren - November 30 - 2:00 am

  Ive had my M45 for about a month now and it is so much fun to drive, yet sophisticated too. It ourpowers my old Jaguar S-Type 4.0 and has all the interior features of that luxury car. Please, it makes a really neat growl when you start it and accelerate.

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  Outstanding - 2003 Infiniti M45
  By icejsmith - November 19 - 10:00 am

  Simply put this vehicle is quick and handles like a sports car should. On top of this it looks great, rides great and has all the amenities of a luxury car.

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  Great Car - 2006 Infiniti M45
  By bob foster - November 12 - 11:00 pm

  The M45 Sport has met my expectations which were high to start with. It is both beautiful and a terrific driving experience. Number one would be the engine and drive train. Best feel of power and control I have ever experienced including BMW540i. It is both design and crafted with excellence and thought. The technology is very good but not quite up to the Acura RL, but I would take the drive train and vehicle design over the technology difference. The features are very extensive and user friendly. One can practically live in the car enjoying all the features and technology. It handles very well at all speeds and conditions as all the reviews showed. I have not been disappointed.

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  My M45 - 2004 Infiniti M45
  By Stafford - October 30 - 12:23 am

  I purchased this car because it had a great review. After the initial purchase my experience was wow! I would love to purchase a new car but I am so satisfied with the overall experience that it make me scared that purchasing another car I will get less. Most new cars are great looking but their performance and overall quality is not as good as the 04 M45. A Mercedes S650 AMG. Talk about money. I guess its the 04 M45 for now and I love. See you on the highway in my rearview. LOL

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  06 M45 Luxury Muscle Car - 2006 Infiniti M45
  By Silk - October 14 - 4:30 am

  06 M45 non-sport journeyman off lease 32k miles. So much fun to drive you just don’t want to get out. Powerful and smooth acceleration at all speeds. All controls are easy to operate. I’m 6’4 & fit very well in terms of head and leg room. The M45 was the right combination of power, ride quality and technology goodies for me. The Bose sound system is wonderful. The M45 sport was just too stiff a ride for me. The M35 does not have the same power, only 1 MPG difference anyway. I bought the Infiniti extended warranty (bumper to bumper) till 100k miles or 2014. Infinity also has the best car loaner program. You always get a loaner (g35) no matter how old or out of warranty your infiniti.

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  Beautiful - 2003 Infiniti M45
  By merimaid - September 26 - 10:00 am

  This is a fantastic fun to own and drive auto. Very unique. Safety, comfort and luxury all in one. Infiniti,has been hard at work.

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  This babe is an eye-catcher! - 2003 Infiniti M45
  By Kenny M - August 25 - 10:00 am

  Ive put on over 5000 miles on the M in just under 3 months...simply put...its a blast to drive! Got it fully loaded except for chrome wheels (looked too gaudy). Got the windows tinted immediately and let me tell you...this car gets looks!! Havent seen a single one on the road yet...feels like a custom-made car. I almost went with the Mercedes C32 AMG and changed my mind...so glad I did.

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  Must have M45 - 2006 Infiniti M45
  By Denis Valle - August 9 - 11:50 am

  Youll be more than glad to take this car the long way home. Plenty of power throughout the power band.

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  excellent - 2004 Infiniti M45
  By wcosmo - July 22 - 10:00 am

  performance, nav and tech package are excellent mine is black/black, chrome weheels make the difference.

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  Additional Comments - 2007 Infiniti M45
  By MMM45 - July 20 - 1:00 am

  I forgot to add that I love the 14 speaker Bose system in this car! 5.1 surround sound is just unheard of in a vehicle until now! Wonderful! The 6-in-dash CD changer and DVD in the center console is great as well! This car is like a mobile home audio entertainment system almost. The heated and cooled front seats are great too!