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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  my m45 - 2003 Infiniti M45
  By c mckee - July 27 - 10:00 am

  This car is in a class of its own. Since the purchase of my m45 I have had many people ask about it. And a lot of thumbs up on the interstate. It is 197in long and 340hp a lot faster than the cars in the 60-70k range. "bmw" "benz" O and the VDC has saved me from skiding more than once in wet weather.

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  M45 wow!!!! - 2006 Infiniti M45
  By bobsM45 - July 21 - 3:53 pm

  Handles as well as my 2000 BMW 540i with greater acceleration. Seats are very comfortable. Sound system, especially dvd audio superb. Build quality excellent.

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  The M45 - 2003 Infiniti M45
  By elagee - July 21 - 2:00 am

  This car is a smaller version of the Q45 but it certainly doesnt ride like it. I can feel every bump in the road. But, if you like power and speed and want to blow the doors off of the car next to you, this is the one. The ride is firm, there is no hesitation in acceleration, curves are not a problem and as the driver you have complete control of the car---no matter how fast you are going. Appointments are nice but not spectacular. Although I have only owned the M45 for a short time I am enjoying driving it.

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  Infinity M 45 - 2003 Infiniti M45
  By valo - July 21 - 2:00 am

  THe turning radius on this supposed sport vechicle is pitiful.It takes two attempts to make a u turn.You cannot make any adjustment to temp or radio with doing two things. Nothing is easy. The driver seat is so uncomfortable. I had 3 Q 45s before this - I made a terrible error in buying this car.

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  Best yet - 2006 Infiniti M45
  By WILLIAM B COSTELLO - June 14 - 6:40 pm

  This is my seventh infiniti and the second m45. This one looks and handles much better than my first one. 335 Hp no way this engine puts out a lot more then 335 hp. The voice stuff takes getting used to. The navigation system is the best ive ever used and very easy. My wife liked the car so much she bought a m35x. The fit and finish are perfect

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  the best bang for your buck you can buy! - 2003 Infiniti M45
  By Donny M - June 9 - 2:00 am

  This car is one of those "best kept secrets" in its price range--but its still new on the market yet, and when the secret gets out, watch out! The power is unbelievable--340hp--and it drives like a dream. The interior is comfortable and ultra luxurious and has great features, especially the voice- activated system--I can access my sound system,(10 BOSE speakers!)or adjust the climate control simply by speaking. If you can live without fancy European names --this is the best car for the value!!

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  A very well built driving machine! - 2004 Infiniti M45
  By Doublewoods - May 27 - 8:16 am

  I have been driving Infiniti M45 since Sept. of 2004. It has lots of power with smooth acceleration and great braking system. Internal design is very well done with almost all of the fancy features you can think of.

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  Jeckyll and Hyde - 2003 Infiniti M45
  By qualityfirst1 - May 14 - 6:16 am

  I still believe this car is a Jeckyll and Hyde. Were still enjoying the power, but the transmission isnt very responsive and the manual mode is worthless. The seats are comfortable and have nice amenities, but the drivers seat squeaks now. We still love all the gadgets, but they are difficult to use. Weve encountered more issues, but we do have 108K miles now. The exhaust manifold was changed under warranty. Now its cracked again - poorly engineered. We still burn a quart every 1,000 miles (108 quarts so far!) Tire wear is phenomenal. The originals ran 28K miles. The second set were Essenzia and were just changed. The new Hankook Ventas dont feel very good on the car.

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  highway cruise - 2004 Infiniti M45
  By ggfires - April 10 - 10:00 am

  A consistant 21 mpg with 80 percent highway and 20 percent city. Outstanding performance and handling for the 2 lane roads.

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  Im in Love with This Car - 2003 Infiniti M45
  By Natalie28 - April 7 - 2:00 am

  Incredible vehicle...designed for a man in this late 40s. Im a women in my early 30s and think this car is the most beautiful Ive seen in a long time. It would have cost me 10K more for an underpowered Mercedes. Yah, that made sense.