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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  Best Performance for the Money. - 2004 Infiniti M45
  By T. Malanka - January 24 - 10:00 am

  I havent found a vehicle in this price range with these kind of numbers. Not to mention the no nonsense styling. Priced similarly to the BMW 525 which makes approx. 184 horsepower. I think I made the right decision.

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  Definitely an all around muscle car and more - 2003 Infiniti M45
  By vitalydelvalle - January 20 - 12:20 pm

  I purchased this car 1 year ago fully loaded with 65k miles on the clock. The car gets loads of attention and compliments, my mechanic always compliments the powerful v8 and many get surprised when they find out the car has 340 horses under the hood. Ive had a few issues with the car, like the fuel gauge inaccuracy which has left me stranded a few times on the road. My camshaft position sensor failed me at around 75k miles. My only complaint is parts are scarce and everything must be special ordered from infiniti. Other than parts issues, recalls, and general maintenance this car is flawless .

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  My 2003 M45 - 2003 Infiniti M45
  By PREFECTO - January 18 - 6:56 am

  I have 22k miles and see puffs of blue smoke on almost every startup. Have scheduled car to have an oil consumption test performed by Dealer. I know the car is using at least a quart of oil every 1000 miles. Dealer has already de-carbonated the engine! To NO satisfaction the blue smoke still appears on EVERY start. They tell me its the advanced oiling system providing more oil in the valvetrain area and just burnoff. Ive Called Infiniti direct, regarding breaking problems. Rotors warped, had to be replaced! Car was only two months old and had to have a new battery! I have spoken to Infiniti Consumer Affairs on three different occassions, which in my case, it has worked!

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  HUH? - 2003 Infiniti M45
  By Randy Tate - January 16 - 2:00 am

  Although Ive only had the car a month... I love it

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  Rot Lot Causes Too Many Tow Ins! - 2003 Infiniti M45
  By FirstTimeInfiniti - January 11 - 7:26 am

  I got a really great deal on a left over 2003 M45 demo with 1200 miles. The dealer advertised $10,000 off MSRP and thats what I paid. $35K for a rwd V-8 is a great deal. But with the deal has come some real reliability issues including new tires (Michelin Pilots) due to lot rot, new battery and a new fuel pump (all replaced under warranty). Ive had this car towed in twice in 6 weeks! I worked for GM for 4 years and am begining to wonder if I bought a Buick! Dealer has made necessary repairs but has done little to build my loyalty. Again, is this a GM dealer? Lesson learned: dont buy a failed model that has sat on the lot for over a year after build date (October 2002).

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  MY M45 - 2004 Infiniti M45
  By PLINA - December 19 - 10:00 am

  I love this car it is everything that I wanted, the only problem that I had with it is that is rear wheel drive and is lousy going uphill in the snow. Hopefully Infiniti will make available an all wheel drive version.

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  AWESOME BABY - 2004 Infiniti M45
  By Wags Nags - December 13 - 10:00 am

  I have had three Q45s before the M45 and this was not a step down. The M45 is a truely enjoyable and fun ride. The M45 handles the road and is much more sporty than the flagship Q. The acceleration is mesmerizing. The driver seat encompass the body like a glove. A splendid vehicle. The only negative is the confusing instumentation.

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  Get Your Motor Runnin - 2003 Infiniti M45
  By Wild Woodpecker - December 10 - 2:00 am

  A terrific car - really is the musclecar with a brain - kills the Marauder - in a class by itself. Handsome and fun to drive..........

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  Gentle Beast - 2006 Infiniti M45
  By sib1948 - December 5 - 1:43 am

  After driving Tahoes for 10 years, I had to buy this vehicle after a test drive. Power and handling are superb, while the cabin is comfortable and quiet. The last time I had this much fun in a car was my 94 Corvette convertible, but now with my first grandchild, I needed a safe car with 4 doors and reasonable backseat space. The frontseats have more room than any other vehicle in its class. The console is easy to use and I can even read all the buttons without my glasses. The Bluetooth handsfree technology works flawlessly, transferring calls from my cellphone into the cabin, when my phone is on in the car. Enough blithering, go take one for a test drive and youll see what I mean.

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  Impressive - 2006 Infiniti M45
  By socal32 - November 25 - 3:30 pm

  This car blew me away, the interior, the technology, the power, the whole layout in my view blows away the Lexus GS430 & the BMW 5 series. Very impressed, and very happy with this purchase. Infiniti continues to impress me more & more.