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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  A Fun Car with Luxury! - 2006 Infiniti M45
  By Walter Little - May 21 - 10:36 pm

  We love our new M45. It has all the luxury features we enjoyed in our 1999 Q45, plus the innovative features such as the GPS and top of the line DVD system. The car will absolutely fly! It has trememdous power, yet it is smooth as can be. It handles and corners quite well, in fact we drove the M45 sport version, and find little difference in how the regular version handles. Although the M45 appears to be smaller than a Q45 on the outside, inside it is just as large, with a much larger trunk. We cannot imagine a better luxury vehicle for the money!

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  unsafe to drive at certain speeds - 2003 Infiniti M45
  By candidph - May 7 - 2:00 am

  Unsafe factors are that the vehicle hesitates two to three seconds when sudden acceleration is required such as for merging lanes in freeway traffic. The cruise-control "collision avoidance" feature tends to cause rear- end collisions because it causes the vehicle to suddenly decellerate when it tries to pass a truck-trailer rig on an adjacent freeway lane, especially on an inside curve. There is a severe blind spot at the left and right windshield post and adjacent car door (where the rear-view mirrors are mounted) for people of short stature like myself, a problem for close manuvering.

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  Not as flashy but just as nice - 2008 Infiniti M45
  By MTCS - April 17 - 3:23 pm

  Traded in a 09 Maxima for the 08 Infiniti M45X. I test drove the 08 G37 and a 08 BMW 550. The G 37 actually drives better but I figured I would get the top of the line and go with the M. The car does not turn heads but as the other reviewer put it, you get pampered when you get inside. I had a Maxima prior to this so I understand all the gadgets. Everything is laid out well. It has great power, you will not get embarrassed on the acceleration lane and on a smooth road you cant tell the difference between 65 and 85. The surround sound is like a concert hall. Around town the ride is a little bouncy, you will feel most bumps in the road and the M goes through gas.

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  Everything you could want and more! - 2006 Infiniti M45
  By Brad King - April 14 - 2:10 pm

  I tested all the competitors(Lexus, Acura, Mercedes, and BMW). The M gives you the most bang for your buck. Ive got the technology package and it is unreal. No other car has all of the features this came with. Bluetooth connectivity for the cell phone works great. The DVD surround sound is incredible. I suggest the Santana Supernatural DVD for testing this sound system. The backup camera is very helpful for parallel parking. The laser guided crusie control is great. You can watch DVD videos on the front screen if you are in park. This is great for when the wife is shopping and you want to kick back in the car. The power in the M45 is fantastic. You could not ask for more. ENJOY!!

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  2006 M45 Sport W/ Aero Kit - 2006 Infiniti M45
  By mario flores - March 25 - 11:06 am

  This newer M45 made a big impact on me after trading in my G35 coupe. The front fascia resembles the Infiniti family tree. The overall styling is modern with a touch of upper level class. The car itself looks great but with the optional aero-kit, it really makes a bold statement. The interior is good but could use better front seat with multi adjustment seat of other cars in the same class. It only offers your basic functions. Good take off from a stand still but runs out of steam after 75mph. Transmission shifts good but could use the 2009 7 speed transmission. Good pricing and good high quality building makes structure solid.

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  Our 4th Infiniti - 2007 Infiniti M45
  By Brad - March 12 - 4:43 am

  We had a 2003 M45, we thought that car was nice. The 2007 is night and day. Beats the 550 in every way

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  BADMOFO - 2003 Infiniti M45
  By pwr-m45 - February 5 - 2:00 am

  For this money (43k)total with both comfort and premium pkgs. my M45 is black on black with natural birdseye maple trim.absolutly sweet.and since infiniti calls it a muscle car i decided to make my m45 look and sound the part.with a wonderful magnaflow exaust system, with that eat my dust roar at full throtle and whisper quiet at cruise(infiniti approved of course,and lovely 19"by 9" chrome blades on 255-40s z-rated.tinted windows all around finished the pkg.I used to droole over the (S55AMG)but now i laugh all the way to the bank.with the money i saved i could buy a commuter and trick out my m45 to absolution!!!

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  My new love - 2004 Infiniti M45
  By Mase2003 - January 24 - 10:00 am

  This is the greatest vehicle i have ever driven. I also own a Corvette, but i would rather drive my M45. it has everything one could ask for in a car, power, luxury, technology and comfort.

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  The Best Infiniti I Have Ever Owned - 2004 Infiniti M45
  By ShirleyK - January 24 - 10:00 am

  This Infiniti looks beautiful and is a pleasure to drive. The car is well built and safe. Passengers tell me it is comfortable as well. The spacious trunk is great, and the navigation system has helped me out in many instances. I am a proud owner of a M45 Infiniti!

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  Dream Car - 2004 Infiniti M45
  By Flick - January 24 - 10:00 am

  Car handles very well and has plenty of power. Navigation system performs well. The intelligent cruise control works amazingly well, even in traffic, however in Southern California it maintains a safe separation distance which means other drivers frequently cut in front.