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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  M45 Sport - 2007 Infiniti M45
  By desertfox - August 24 - 11:56 pm

  Purchased this car used w/27,000 miles on it. CPO Infiniti. Im a Lexus guy and still own one but this car really opened my eyes. The ride quality is great, no issues with sport suspension. Interior is quiet as any luxury car I have ever driven. This car takes no backseat to any German luxo sedan out there.

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  Sold on Infiniti - 2008 Infiniti M45
  By 1st Infiniti - August 22 - 10:46 pm

  I purchased a 2008 M45 Sport in December. It was "used" with 3,700 miles and includes the Sport, Tech and Advanced Tech packages, which are just about everything youll need unless you are shuttling around some very special friends. (The only thing its missing is the reclining, heated rear seats... boohoo.) I looked at dozens of cars before finding this one at an incredible deal. Giving up a Porsche 911, I wanted power... check. I also wanted something luxurious... check. All without making me feel like I should be twice my age in order to drive it... thats where the Sport Pkg comes in. This car handles incredibly well for something this big and the acceleration nearly matches my 911.

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  Wife changes mind about M45 vs Q45 - 2006 Infiniti M45
  By Rosa Lee - August 20 - 4:30 am

  My husband purchased an M45 a month ago and initially I felt it was not as satisfying as our 2002 Q45 due to firmness of ride and being slightly noiser. But after driving it and having it this past month, I have changed my mind 100%. I love driving it and after lowering the tire pressure find it is not noisey at all. It is the best of the 7 Infinitis we have owned, (all Q45s except for my G35 Couple)

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  the perfect car - 2006 Infiniti M45
  By chris fisher - August 13 - 12:20 pm

  This car has so many toys I never get tired of them and the power is great my last car was a acura NSX 03 so I know what I am talking about. 19" rim back up camera dvd player navi rear stearing that loves to be pushed in to the corners I took a few of my friends for a ride and when we returned they all said WOW!! Now we see why you picked the m45 1/4 mile 13.8 0 to 60 5.6 thats crazy oh and my supercharger is in the works extra 100 hp cant hurt......

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  M45 Sport (Mmmmmm !!!) - 2006 Infiniti M45
  By Don Juan - August 8 - 11:50 am

  Excellent car and fun to drive ! More car for your money compared with other cars in similar categories. I get around 17-18 MPG, but whos complaining if you can afford a car over $50K. The sports package really makes a lot of difference if you like a little hard driving once in a while.

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  Great car - 2007 Infiniti M45
  By andy - July 21 - 3:16 am

  Ive driven BMWs 12 out of the last 20 years. Went to look and prices were out of site. Drove 530, E350/550, GS 450h, Audi A6 then the M45. Drove out loaded advanced tech package, spoiler and rosewood. Car is a dream. Has every luxury item that the Germans nickle and dime you with. Very smooth but powerful acceleration. Quiet comfy interior, great stereo and nav, ac seats are great in florida.

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  Excellent Value - 2003 Infiniti M45
  By DarenP - July 6 - 2:00 am

  Ive had this vehicle for almost 6 months and its my favorite of all time. It really is the muscle car with brains. Lots of comfort and lots of power! A real blast to drive, yet a lot of comfort inside. And the price is a steal compared to its competitors. Id highly recommend this vehicle.

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  Disappointed - 2006 Infiniti M45
  By Lee - June 25 - 10:16 pm

  Purchased the M45 after owning a BMW 525, then a 2000 740IL. The Tech package of the M is awesome. Love the 3D GPS, voice activated controls, rear backup camera, A/C control seats (could be better), and overall looks. But from the very first oil change, have noticed using oil; not leaking, not smoking, but I have added from 1 to 2 quarts between changes. Also, moonroof leaks in any car wash, have had to have the AC serviced each year. Heated and cooled seats do not compare to the BMW. Ride is noisy, low-profile tires look great, but makes bumpy ride. If battery dies, no way to open the trunk (for jumper cables).

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  Infiniti m45 sport - 2006 Infiniti M45
  By vINCE - June 22 - 12:26 pm

  A great drivers car...Quick, responsive,extremely comfortable. Traded in a lexus ls 430 (2002)and have not looked back. I lost a minimal amout of interior space, which is more than compensated by a superior drive train (featuring a great v8),more and very intuitive technology and a great array of safety features

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  Fantastic Car, Buy it Now! - 2003 Infiniti M45
  By Up from Volvo S80/T6 - May 25 - 2:00 am

  Terrific package for a price thats many thousands less than "comparable" GS 430, E500, and 540i. Powerful, smooth, responsive, fun to drive. And NO turbo lag like the Volvo S80/T6. Used manual shift mode in MW snow today and had no problem moving this rear drive car in 8" unplowed shopping center lot. This is the car GM should go after with a GTO badge if they want to get back in the game. Get double take looks everywhere, which you see in the rear view mirror as you zoom past! This will be a hot model for Infiniti, on top of their award winning G35.