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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  Extremely Recommended - 2007 Infiniti M45
  By Lars - November 13 - 12:50 am

  I test drove Volvo, Saturn, BMW, Mercedes, Audi and Lexus. None of these other cars are so much fun to drive with such great technology features as the Infiniti. My M45 is fast, easy to drive, comfortable with more leg and head space than Audi, BMW or Mercedes has. What a smooth ride.

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  Look no further - 2004 Infiniti M45
  By Tbone - November 4 - 3:43 am

  I havent loved a car this much since my 88 Mustang Conv. GT. The 2004 M45 is fast, comfortable, anf hot with all the jazz. I stopped talking to the car after two weeks (voice activated stuff is cool but useless once you know what to push). In a car with this much electronics and intelligence, the analog clock is a wonderful touch. The interior is gorgeous.

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  M45-Great Car! - 2003 Infiniti M45
  By BobH060941 - November 3 - 10:00 am

  This is a terrific vehicle-powerful and fun to drive. Only 2 shortcomings: fuel economy and turning radius

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  Awesome Car! - 2003 Infiniti M45
  By atsu8 - October 3 - 2:00 am

  Ive had my M45 for about a couple months now and this car is a rocket. I really dont understand the "experts" saying its a ugly car. I get looks everywhere I go and people love it. Super fast!

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  Great Car!! - 2003 Infiniti M45
  By BB 7557 - September 27 - 10:00 am

  I love this car. Awesome power, very tight stable ride. Dont understand all the auto magazine gripes: It takes all of 10 minutes to figure out the radio/climate controls, and then its completely intuitive! The car draws stares from loads of onlookers. I still have not seen another on the road, and while that made me a bit nervous , it does give it a real sense of exclusivity. Build quality is typical Infiniti (Wife has the QX-4). This is the first automatic Ive ever owned, but its nice, and the manual mode works better than I thought it would... If you like this car, drive it and buy it

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  Fun Ride - 2003 Infiniti M45
  By biorid3 - September 21 - 10:00 am

  This car is truly a wolf dressed in sheeps clothing. Its benign exterior looks give no indication of the monster under the hood. Acceleration is "push you back in your seat" quick, and handling is precise. Anyone who picks a fight with this car will lose. Its insulting to this car to obey speed limits. Yes, trunk space is poor, they have wedged the fuel tank in between the rear seat and trunk. Alledgedly this is a safety issue.

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  Better than Benz - 2003 Infiniti M45
  By WACl - September 15 - 2:00 am

  The M-45 has better suspension and more comfortable seats than the Mercedes S430 that I traded for it. Exhilarating performance and lots of neat technology features, such as DVD based GPS, laser controlled cruise control, tire pressure readout, and satellite radio. All at reasonable price. I cant understand why I dont see more of them on the road.

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  Still drives very well - 2003 Infiniti M45
  By qualityfirst1 - September 5 - 6:00 pm

  This car had lots of positives, but the few negatives does sour our ownership experience. Our M45 has a very unique look, which Ive come to like. The interior is still very nice. Our car still drives very well - it doesnt feel like 108K mi. The power is very impressive. The aluminum suspension components cut unsprung weight. A lot of things have broken, which is upsetting. Infiniti service writers are nice, but they will not fight for the customer. Our air bag light has been on since a hair over 50K mi. The warranty is good up to 7yr/70K, but they wouldnt fix it. The oil issue stinks. Due to the bad service, I wont buy again.

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  My last car - 2007 Infiniti M45
  By brobob - August 12 - 3:06 am

  I have had my eye out for this car ever since I heard there would be a replacement for the Ms. Right away I loved the look of it from every angle. My last car was an Infiniti and I have found that Infiniti treats its customers right. It has the good power that require. When I first heard the 5.1 sound system I was sold. The car feels and sounds solid. A little too much road noise when the road has thumps. Other than that I love the car.

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  Awesome Ride - 2006 Infiniti M45
  By Burn-It - July 16 - 5:06 pm

  I love it when BMW 5 series owners start messing with me - after I toy with them a little while, they are just a spec in my rearview mirror before they knew what hit them. The M45 Sport Tech is awesome, has incredible torque through all ranges. I compared this against the Lexus GS430, AudiA6, MercedesS430 & BMW545. The M45 Sport has all of the strongest features of each of those 4 wrapped into 1 incredible luxury rocket ship! Very roomy interior and trunk. Although Lexus has a few more electronic gadgets, I like the M45 navigation and heads-up controls better. The interior rocks, not a bunch of plastic like Lexus and not cold like the German makes. No wonder all the mags rated M the best.