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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  Ivory Pearl - 2003 Infiniti M45
  By Ivory Pearl - April 14 - 8:10 pm

  This vehicle is reliable (at 90K miles) and still drives the same as when I drove it brand new off the lot. As an engineer, this car has all the technological gadgets one could want or need. Amazing driving performance (power - 340HP & 333 ft.-lb. of torque and handling) and style. I havent had any issues except a recent gas gauge replacement by the manufacturer. This vehicle is incredible when I compare it to previous vehicles such as: 1991 M3 and Acura 3.0 CL.

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  Infiniti M45 - 2004 Infiniti M45
  By Denis Cagna - April 13 - 2:00 am

  Purchased one year ago (have identical 2003 model). Greatest feature is the seamless power from the engine. Beautiful. It is also a terrific value for the price.

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  Nice ride - 2003 Infiniti M45
  By Rnewell - March 8 - 2:00 am

  I was surprised to read the knocks on the body style. I added a spoiler and tinted windows and in the first week was stoped and told how nice the car looked. The best part in the performance the car is a rocket on wheels. As a prior BMW 540 owner I think this is just as fun to driver with a much more reasonable price.

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  03 INFINITI M45 BEST CAR EVER OWNED - 2003 Infiniti M45
  By mike s - February 23 - 12:00 am

  Best car i ever bought.Paid 15,000 with only 88,000 and a full elite Infiniti warranty.had major oil burning issue which Infiniti took care of and replaced L.B. @ 96,000. Fun to drive,very fast,and looks great.

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  Very Refined Hot Rod - 2006 Infiniti M45
  By Rob Conley - January 27 - 6:43 pm

  After driving many competitors, selected the M45. What a wonderful car. Very luxurious and spacious for four people. The interior is very well done, liked (and got) the wood accents. This is the best handling and quickest sedan I have ever driven. The manual-shifting automatic works MUCH better than others Ive tried. The shifts are very smooth, and it feels like it is meant to be used. I use it 90% of the time. The engine is just great, capable of quick acceleration from any speed. The navigation system has a learning curve, but is very useful and the voice feature actually works! Also like that the computer system supplements, but doesnt replace the audio and climate buttons.

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  a BMW with a 50% discount - 2008 Infiniti M45
  By Ray Libaad - January 12 - 4:20 am

  I bought this after testing the 550i. outstanding performance. Handles like a sports car but rides like one (19"wheels). Interior is quiet and serene at high speeds. I find myself regularly doing 100-120mph without even feeling it. Exhaust note is sweet. The best low beam headlights in any car Ive driven (the road is evenly carpeted with bright white light) but strangely very lousy high beams. Leg room in the front and back is class leading

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  Preety Good - 2003 Infiniti M45
  By robertem1 - December 19 - 10:00 am

  Ive had my M45 4 months, and 5K miles. I took a long trip out west with it and got to work it hard. I got excellent mileage (23-24) at highway speeds. I love the power and can almost get the numbers that the magazines do. It handles very well at triple-digit speeds and is smooth and quiet. I experienced a problem with the tire pressure monitor, but once reset, it worked just fine. The interior looks very classy and elegant. The only things that I dont like are the transmission shifting and lack of bass in the stereo. It is just a shade short on headroom too. I will live with that for the $18 K under the Cadillac I WAS going to get.

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  Fun Drive - 2003 Infiniti M45
  By poli27 - December 13 - 10:00 am

  My former daily driver was a BMW 540i. This car is much more comfortable with superior build quality. While it doesnt handle as well as the bimmer, the acceleration and overall performance is impressive. This is our fourth Infiniti (between my wife and I) and a very pleasant choice.

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  Whats not to like? - 2003 Infiniti M45
  By barcou - December 9 - 2:13 pm

  Bought a used, loaded, black 2003 M45 and it is as perfect as I think a car can get. Matter of taste of course, but I think it looks great (esp. from rear 3/4 angle). Drive is tight and sporty but not harsh. Feels a lot lighter on its feet than it should -- very planted though. Has that rare car appeal since you dont see very many on the road. The odd stare once in a while. Reliability not an issue, unlike my 325i. All in all, just about perfect. Only gripe is when radar lens cover gets gummed up (I live in Calgary, Alberta), it shuts down cruise control altogether.

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  Best V-8 deal going - 2004 Infiniti M45
  By Robert - November 23 - 9:40 pm

  For $40k, this is the best V-8 deal going. Scary fast, pretty quiet, great dealer, better than average warranty, and lots of interior features.