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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  Wolf in Sheeps Clothing - 2004 Infiniti M45
  By nbeyond - March 5 - 5:36 am

  Went in to look at the G35, but was not as impressed with that car as reviews had led me to believe. Actually hadnt heard of the M45, but was immediately attracted to the interior design and comfort before I drove it. Then, wow! Clearly, a refined muscle car. You just dont expect to get quick acceleration and tight handling from what is essentially a luxury sedan. The Edmunds review compares the looks to a Cadillac DeVille, but with the rear spoiler and after adding custom chrome wheels, they couldnt be more wrong. I drove the Cadillac STS-V and BMW 545 before picking this car--couldnt see a good enough reason to spend another $10-15K. And, gotta love the reliability reports!

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  best experience ever - 2007 Infiniti M45
  By KANDICE - March 3 - 3:06 pm

  unbelievable! I have had over 10 luxury cars and this by far is the best ever!

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  Best Performance Luxury Sedan - 2006 Infiniti M45
  By shmang - February 22 - 2:40 pm

  This car is simply amazing. With the luxury and performance combined together, few can match. Infiniti gets it just right. It is packed with luxury options to make it a true luxury car, while the 335hp V8 with firm suspension makes the car a true performer. It is not a sports car for sure, which it should not be, as it is a luxury sedan. This car makes the trip enjoyable no matter drive it fast or slow.

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  Way Cool - 2003 Infiniti M45
  By Alan Acosta - February 13 - 10:00 am

  I moved from a BMW 330 coupe to the M45. I enjoyed the BMW, the M blows it away for just a few thousand more. The BMW was more sporty, felt the road more, yes. all thats true. But given all those people in their automatic 325 sedans, I think that argument is hooey. The M drives really well and knocks you back in your seat when you take off. Build and fit-finish are excellent, gadgets fun. Finally, the M has taken its knocks for its "look," --too conservative, too chunky, whatever--but I have gotten rave reviews from friends and people on the street. Lots of power and bang for buck--this car rocks.

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  A Real Sleeper - 2003 Infiniti M45
  By troxl - February 7 - 10:00 am

  You dont see this one coming. It has class, features, and a 340 horsepower V8. This car outclasses my Bonneville SSEi.

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  hot car - 2004 Infiniti M45
  By fariaro - January 21 - 10:00 am

  My only complaint is the transmission. It is rough and at certain rates of acceleration appears to not have enough torque for that gear, then downshifts.

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  World Class - 2003 Infiniti M45
  By hofame - January 7 - 2:00 am

  Safety, Power,sure footed responsiveness, Cost, Technology with a dash of analog ... make the M 45 a World Class vehicle. A must test drive for those that are in the market for a quality vehicle. Toyota, Lexus, Mercedes, Volvo take a back seat for similar vehicles in the same price range.

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  MIND BLOWING SPEED! - 2003 Infiniti M45
  By gray_M45 - January 7 - 2:00 am

  My wife and I we about to buy another BMW 745i when we saw this car at the car show. I bought one the next morning after driving it. And I saved about $40K. I cannot believe the power, handling, technology, comfort and refinement of this car. Lets not for get the price, mine is loaded and it is still under $50K. I get more comments on my M than my wife gets on her brand new $82K BMW, and I can beat her car any time any place. Needless to say she cannot wait to get one.

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  Expensive: Low Quality Features - 2006 Infiniti M45
  By dembinsk - December 13 - 4:43 pm

  I have owned a 02 BMW 330 sport sedan, a 03 BMW 540 sport manual 6 speed, and finally decided to give the japanese a try. The Infiniti M45 is by far the closest feel to the germans you can get in a japanese sports sedan. Great reliability, great styling, and many features. Problem with the car is the horrible gas mileage averaging 13.5 MPG in the city and thats 3.4 MPG less than my BMW 540. Tons of features but they are all low grade. For example..the seat heaters dont even compare to the BMWs, the sound system is very hollow and tin sounding (plastic like), shared dashboard gauges from the Altima, and last...the suspension is horribly rough on everyone in the car.

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  Powerful Sport Sedan - 2003 Infiniti M45
  By qualityfirst1 - November 30 - 9:13 pm

  This car intrigues you. A true Jekyll and Hyde. Lots of power - Manual mode on transmission is worthless. Comfortable seats - Hard to reach seat controls. Nice wood and leather interior - console and glove box are loose. Lots of goodies - Too many steps involved to enjoy them. Feels great up to 120 mph - feels unsafe at 125 mph. Big car - Interior feels narrow. I like the handling and performance of my car, but it does not have give you feedback like my BMW 540i. This car is a sleeper. You can pull away from nearly every car on the road. Stereo system is very nice. Ours is black with tinted windows and chrome wheels - I think the best color for this car. Engine burns lots of oil!