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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  Bargain of the century - 2003 Infiniti M45
  By sar - January 27 - 10:00 am

  Second infiniti owned, and second loved. Great cars all-around, and what a bargain. Why pay $10,000+ for a comp. equiped BMW or Merc? This car is beautiful. Had a jag owner dying over the specs and price.

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  Dont drive the M45! - 2006 Infiniti M45
  By Vulcan - January 3 - 10:06 am

  I purchased my M45 sport with tech and journey packages 3 weeks ago and all I can say is WOW! This is far and away the best all around car I have ever driven in this class. I test drove BMW 5 series, Audi A6, and Lexus GS430 before I purchased the M and in my opinion the M blows them away. The rear active steering (RAS) makes a subtle but noticeable difference in turning and cornering. The intelligent cruise control absolutely spoils you for long commutes! Why not drive the M45? Well, if you drive the M35 first (6 cyl,280 HP) , youll love it. But if you then drive the M45 (8 cyl 335 HP) youll never go back and it will cost you $7,000 more!

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  First car I ever loved... - 2006 Infiniti M45
  By sdcal - January 1 - 11:13 pm

  I have almost 3000 miles on my M45 Sport and have enjoyed every single one of them. Even those when I was stuck in S CA traffic. The car is very fast, very fun, and very comfortable. I do not understand those that compare the car to a maxima or G series Infiniti. Theres no comparison.

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  M45 - 2003 Infiniti M45
  By M45 - December 25 - 3:36 pm

  One of the best cars Ive ever driven next to the Mercedes cars. The car is a head turner to most, but is subject to criticism by a few due to the styling, but that makes it all the better. This car doesnt follow the same lines or mold as the other cars. Infiniti stepped outside the box on this 03-04 M45 setup and Im glad they did. The car is strong and handles well in the straight away. I havent had any issues since I bought it in 2005. No gas gauge or oil issues.

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  fantastic car - 2006 Infiniti M45
  By JEFF - December 21 - 9:40 am

  This car is really fun to drive; terrific acceleration on the freeway. As a former Lexus owner, the road feel of the M45 is a welcome change from riding in a cocoon. The dash console is attractive but a little confusing. Sirius satellite radio is a big plus.

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  Love it - 2006 Infiniti M45
  By Kent - December 11 - 8:00 am

  I originally was going to buy the GS 350, but after driving it several times, I felt cramped and I couldn’t even sit in the back seat with out slouching over. Once I drove the M45, it has plenty of room and power (more than the GS430) and costs less. Its a very civilized hot rod! Love it!

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  Best Performance and comfort - 2004 Infiniti M45
  By Sam - November 26 - 11:00 am

  Best Sedan performance plus quality for the money in America, specially 1-2 yr old used one. Smooth and quiet at high speeds. Great stereo.

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  Most bank for the buck!! - 2003 Infiniti M45
  By TWD in Austin, Tx. - November 20 - 2:00 am

  I bought the first M45 in Austin and smoked a Porsche Boxter the first week. I looked at the new E500 and there was no comparison, especially for the price. Ive had three Corvettes and this one will definately keep pace with my 93 and seems to handle better, suprising for a large four door sedan. Looks best in Black with chrome wheels. Very 70s in style which I like but with far more technology. Though Ive had mine now for two months, Ive seen only one other one here. It appears this car will be another "sleeper." Ill have fun smoking other "so called" competitors: 540i, GS 430 and E 500.

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  NO COMPLAINTS AT ALL!!!!! - 2003 Infiniti M45
  By JAYYOSH - November 20 - 2:00 am

  THIS IS AN AWESOME VALUE FOR THE $$$S FOR THE SAME AMOUNT, YOU CAN WASTE YOUR HARD EARNED MONEY ON A 6 CLY. BMW 530 OR A 6CYL. LEXUS GS300. A VERY HIGH RECOMENDATION IF YOU WANT TO GET ANY OF THESE VEHICLES. ALL I HAVE TO SAY IS, 340 HORSES!!!! ANY QUESTIONS????

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  Best car yet! - 2007 Infiniti M45
  By dfcarter24 - November 15 - 1:20 pm

  Being my first sedan since my 1989 Ford SHO, and many Suburban and pickups in between, I spent 1 year researching and dreaming of what I wanted in a sports sedan. The Infiniti M45 Sport has exceeded all my expectations. My only complaints would be the poor fuel mileage (what did I expect in a 335 hp hot rod?), perceived need for a six-speed transmission, and the non-effective high-beam headlights. But these complaints would not deter me from buying this car all over again. I probably should have sprung for the Bose 5.1 surround-sound system, but the regular Bose system is certainly no slouch. Fresh off a mountain romp through the twisties, the smile on my face could very well be permanent!