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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  Incredible Car - 2003 Infiniti M45
  By gregor500 - November 17 - 2:00 am

  The drive is incredible and the price in the relation to the power gives it gives you makes you look silly to buy and e class or 5 series.

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  The New Benchmark - 2006 Infiniti M45
  By Dr. E. Brown - November 1 - 6:03 pm

  The Infiniti-M series is the new benchmark in this class without a doubt. It takes all of the good qualites of the Lexus GS and BMW 5- Series and combines them into one complete package. The car is quick and handles well, and it feels like a real luxury car. The interior is beautifully finished and the exterior is very nice looking. This car has almost every feature someone could possibly want. Infiniti has hit a grand-slam with this car.

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  Wolf in Sheeps clothing - 2003 Infiniti M45
  By gbolton - October 31 - 10:00 am

  If you are looking for pure heart pounding performance this is the vehicle...Ive only had my car for 1 week and all I can say is I never knew an Infiniti could have this affect on a human being....nothing and I mean nothing can touch this beast.....they also have great deals right now....hurry.

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  Good fast car. Always in front. - 2003 Infiniti M45
  By Jack Orr - October 31 - 10:00 am

  The car is not as well packaged as the A6-there is less knee room in back and a very skimpy trunk. But, I found the reason for this is that the fuel tank is located between the back seat and the trunk. The safety benefit of this is obvious. The body is not what I would call a leading edge design. The paint job is excellent, everything fits, the doors close well. Fit and finish is top rate. Suspension is very good. Steering quite up to the task. The most outstanding feature, by far, is the engine. Oh, a last thought. The body is very rigid. No groans or squeaks. And it promises to be very reliable.

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  Better Than All Competitors - 2008 Infiniti M45
  By Mouseclick - October 19 - 4:30 pm

  After thoroughly reviewing several cars from BMW (3 and 5 series), Jaguar (XF), Mercedes (C class), Lexus (IS F), I settled upon the M45 sport, almost fully loaded (lacks mobile DVD system). Some of these cars are like comparing apples to oranges but, the M45 above all others is best in overall value to performance – it has the best of all worlds. It offers great performance, plenty of space, excellent design and the best technology features of anyone. While all the other cars were always sorely lacking in some features (for example, the IS F lacks space, the Jag lags in technology, etc.), the M45 simply glimmers best in everything overall, and at a respectable price comparatively.

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  A lot of car for the money! - 2004 Infiniti M45
  By Enrico Gamboa - October 19 - 2:00 am

  I wanted a Mercedes E500 since Ive been driving Mercedes cars three years, but it stickers for $63k with the options I like. I decided to look at the 2003 Infiniti M45. The performance is fantastic! It looks great inside with plenty of new tech equipment and the exterior design is classic and modern. It has 340 hp compared to 302 hp in the Mercedes E500 and $17000 less on the MSRP. WOW!!! I love this car.

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  infinite wisdom - 2003 Infiniti M45
  By chadwick miller - October 11 - 12:50 am

  this is the best car i have ever had it really moves and am getting 21 miles per on average

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  Goes like a bat outta hell ! - 2007 Infiniti M45
  By Rando - October 3 - 10:00 am

  Car is fast ! Handles extremly well in sweeping curves exiting off the highways, no one can keep up least of all those tail-gating SUVs, LOL ! Downshifts are awesomely quiet.

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  M for Muscle 4.5 V8 - 2003 Infiniti M45
  By TJ - September 21 - 7:56 pm

  I bought a used 2003 M45 in 2006 with 28000 miles on it. It is black with brushed aluminum wheels. It also has hand painted silver and gray pinstripe along the length of the vehicle. This picks up the chrome and the wheels nicely. This car is a beast on the road. I have complete confidence in the capabilities when highway driving. The car is very stable. Stays flat on the road. No pitch or yaw issues for a car of this size. There is more than enough power to get you in/out of trouble ;)... The V8 is smooth and responsive. It responds with a growl during acceleration at any rpms. There is no equal for the money. What a value!

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  Long term love affair - 2006 Infiniti M45
  By cammer - August 30 - 7:11 pm

  Wanted to give a long term persepctive on the M45 (Sport) I have put over trouble free 60k miles on the car. I must say it has surpassed the high expectations I had when I bought it 5 years ago. I had purchased the car after Car & Driver rating it higher than the 5 series. I drove several of the competitors and was sold due to the handling, power, technology, build quality (only Nissan built in Japan in 06) and vale. It price out 15k less than comparable BMW, lexus & Mercedes. The car continues to deliver all the positive traits to this day!