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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  Professional Reviewers Are Wrong - 2003 Infiniti M45
  By CincyRon - September 12 - 10:00 am

  Best luxury car for the money. I traded a Jag S-Type (Taurus in a cat suit) for a sports sedan that beats it in every category. Car magazines are down on the exterior looks, but I the design grew on me overtime. Once I test drove the machine, I knew it was a superior car to the Jag.

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  This is a hidden GEM!!!!!! - 2003 Infiniti M45
  By Krattzzman - September 1 - 10:00 am

  one week and 1,000 miles already. This car is FAST but get ready to fill the tank. This is a muscle car as well as a luxury car as well as a head turner.

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  M45 Hi- Tech Executive Jet! - 2006 Infiniti M45
  By Cammer - August 18 - 8:53 pm

  I have to say that I still have the same grin on my face as the day I bought the car. I have never driven a sedan that handles this well. I like to drive aggressively on mountain roads and the M is willing partner. Passengers are blown away by the technology, GPS, bluetooth, self adjusting cruise, lane departure warning I could go on and on. I have yet to have any problems with the car, just oil change. Did I mention the Bose 14 speaker sound! This car is tight! 12 hour drives are piece of cake!

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  Great Car / Little Annoyances - 2003 Infiniti M45
  By DC - July 31 - 12:13 am

  I bought this car used, Have had it one year now and love the car. Its a great car, but has these little annoyances that frustrate me to death. 1. Oil consumption. Have never owned a car that I have to put so much oil in (50,000 miles on it). 2. Glove box droops down, very annoying. 3. Trunk never opens enough so that auto shut doesnt catch it and close it again. What a pain!

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  Vive La Differance - 2003 Infiniti M45
  By rick fish - July 14 - 2:00 am

  Very easy to drive at a high pace. Nose is UUUgly. Like (no, love) the rest!! Just bought one for my wife at $2500 under invoice and 1.9%, cant beat that with a stick. MY wife is no lead foot but the 3x Ive been on the highway with her shes cruising in the 80s and quite unawares.Fit and finish impeccable. Interior materials equal or better the competitors(excepting Lexus)

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  Rear Clunk - 2008 Infiniti M45
  By M Ashley - July 11 - 9:33 pm

  Love the car but I have a clunking noise coming from the rear of the car. Infiniti knows about this & its been with the M series since 2006. They say its "unfixable". WHAT??? I am very displeased with the way Infiniti is handling this problem and plan to take it to the fullest, if it should come to that.

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  M45 Sport - The True Positive & Negative - 2006 Infiniti M45
  By Dale Fredrick - July 4 - 9:43 am

  Positives: 335 HP V-8 engine is superior to all others, very smooth & powerful. Seats are very comfortable for long drives,ventilated,lumbar. Voice commands,Bluetooth,NAV,Bose Studio 14 spkr DVD audio & technology features superior. Reliable electronics (Japan),100% Japan parts content & assembly. Awesome tech & features for price point. Negatives: Headliner "clicks",intermittent rattles,road feel & handling feedback compared to new BMW 5 Series is poor,wheel balance on front right was way off. Quirky steering wheel movement on freeways requires continuous tiny hand inputs probably due to 19" tires and sport suspension setup(too tight)After 3000 mi.& 3 months sold car to CARMAX for $48,000.

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  Great choice in this segment - 2006 Infiniti M45
  By DJ - June 2 - 10:43 am

  Purchased used w/4,000 miles, all options except DVD screen and heated rear seats. Great performance and handling for such a large car. Tested Lexus GS 430 and BMW 530 but M45 seemed much roomier in the back and quicker as well. Love the soft leather and rosewood, even though Lexus still more refined inside. Exterior styling also a little bland compared to E500 and GS 430. Nice exhaust rumble thats not intrusive when cruising at highway speeds. Glad I dont have sports suspension, supple ride thats only occasionally harsh over very large irregularities (especially if accelerating hard). Rides a bit noisier than Lexus, but expected given sporty personality.

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  Love My M45 - 2004 Infiniti M45
  By JoeK - May 15 - 10:00 am

  Whats not to like - 120 more hp than the BMW 530 and 40 more hp than the Lexus GS 430. Plus the car has a longer wheel base giving it a smother ride. Last but not least, the stereo system is about 100+/- watts more than the cars the M45s class and is equipped with Bose speakers. There just too many details to go into - 18 inch wheels, nav system, price, Infinity customer service....

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  The Dream Car - 2006 Infiniti M45
  By M45 - April 27 - 3:00 pm

  If you ever wanted a car that could do everything, the M45 is the car for you. It comes with every accessory known to man. Its one of those cars that you enjoy getting into every day to go to work or go on an outing. No matter where you go, people will be looking and admiring what you are driving. I have owned in my life time at least 12 vehicles from different makers and I can honestly say, I have found a home with the Infiniti M45.