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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  Great car, very fast + lots of fun - 2007 Infiniti M45
  By freshpavement - February 25 - 6:30 am

  After test driving almost every model made by BMW, Mercedes, Audi & Lexus, I was surprised that the Infiniti M45 was the most comfortable, fun to drive and intelligently designed of the bunch. I wanted a 4-door sedan, so during the test drive I put my 63" son in the back seat and he had plenty of leg & headroom (not the case with the BMW 5 or 7 series, nor the Mercedes E or S Series). The electronic systems are easy to use - I pretty much had it down after the first drive. Its a really fast car - in fact, Ive had to talk my way out of two speeding tickets in the year Ive owned it. No problems whatsoever, great sound system (I got the sport model with the nav/tech package).

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  Move Over Lexus! - 2006 Infiniti M45
  By Bill Little - January 14 - 6:00 am

  Having driven luxury vehicles for the past 12 years, I can truthfully say that my Infiniti M45 is the finest auto I have ever owned. Its just flat fun to drive, it has awesome power, particularly low end power, enough gadgets to satisfy even the most demanding technocrat, and styling that equals any vehicle in its class. No wonder its rated so high. Its got my vote.

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  Longevity, I wonder? - 2003 Infiniti M45
  By Roadglide99 Revised - December 21 - 10:00 am

  I have 30k miles and see puff of blue smoke on cold start up along with a broken driver seat cooling switch. Dealer had car for two wks. Told me it needed engine de-carbonization and a broken wiring harness in the seat. To NO satisfaction the blue smoke still appears on EVERY cold start. They tell me its the advanced oiling system providing more oil in the valvetrain area and just burnoff. I say BULLSHIT! Called Infiniti direct, they said whatever the dealer says is what they go by. I cant speak to a regional rep., nothing. My only course of action see another dealer and get a second opinion. Gee, thanks for the help Mr. Manufacturer!

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  Better Buy One...Its "HOT" and "Fast" - 2006 Infiniti M45
  By sho3000cc - December 11 - 3:13 pm

  The M45 is almost perfect for me. I like the whole package with the exception of only a few things!!! It handles like a 2door sports-coupe and roomy enough for 5. This car out-runs most sports-cars!!!! Lifes too short, so buy one now!!!! My lexus gs400 seats , fits me somewhat better but the M45s seats, has more lateral support. They should put Michelin a/s Pilot sports on this car. That would give a 10 out of 10 ride quality instead of a 9 out of 10. Youll also be able to drive it in the snow !

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  Everything you want, no worries after! - 2003 Infiniti M45
  By Happy As Can Be - December 7 - 10:00 am

  I, too, had considered BMW/Audi and shyed away due to concerns about maintanence. Lexus dealer didnt have what I wanted to test drive(GS430) and the LS430 felt like a boat (on 16s!!). Took this baby out and the decision was a "no brainer." A dream to own, yet its not a nightmare for your mechanic and reasonable to insure - for less than my old Volvo (check out Wawanesa.com).

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  Infiniti M45 - 2003 Infiniti M45
  By deraye - November 19 - 2:00 am

  I have had the car for a little over a year doing predominantly highway miles and have enjoyed the power and the ride. However the car is a little large to "throw" around corners and that detracts from some of the pleasure. I have driven through three snow storms, and the rear wheel drive handles well on ice and snow. Dont care for the "manual" which essentially is an automatic that you "walk" through the gears.

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  Great car--low gas mileage - 2006 Infiniti M45
  By SteveB - November 9 - 5:36 pm

  The Infiniti M45 handles like a sports car. It has cutting edge electronics-- the best navigation system available, laser cruise control, keyless ignition, rear camera, an audible warning if you get too close to the white line. Based on my experience, reliability is excellent. The only negative: 15-16 mpg. Since I drive about 8000 miles a year, the low milage doesnt cost me very much. To me, its worth it to have such a high performing, comfortable and technologically advanced car.

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  What a ride! - 2003 Infiniti M45
  By wslowry - November 5 - 2:00 am

  The acceleration in this car reminds me of a 1968 Road Runner I had in my twenties except this car corners. I traded in a BMW 740I and in some ways this is a step down but in many ways it is an improvement. The A/C in the seat is great for the climate here in Florida. The warranty is 4/60 bumper to bumper and 6/70 drivetrain with lifetime free road assistance - hard to beat. The styling may not be your cup of tea but I can tell you it is an impressive vehicle to see in person - its obviously a car of substance. The extra 50 horses over the 5 and 7 series bimmers is going to come in handy I suspect. Gas mileage is a little scary though.

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  Love it and for the money.... - 2008 Infiniti M45
  By sunpower - October 8 - 2:33 pm

  I leased mine with a two year contract. At the end of the lease, I am very happy with the car. It has good acceleration, its comfortable and its stylish but not over the top. It doesnt attract too much attention but when I sit inside I feel pampered. Good features are ride and technology. Bad features are gas mileage and noise level.

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  M45: Fun to Drive - 2004 Infiniti M45
  By hambone1958 - September 20 - 10:00 am

  I bought my wife an M45 for Valentines Day. This car is supposed to be a mans vehicle. But, she picked it out and fell in love with it. 340 Horsepower V-8, great interior, great styling. Did I mention 340 H.P.? Seriously, I consider all that power a safety item. It will get you out of many tight spots on the highway. If you need to pass, there is PLENTY of power. The interior is comfortable and beautiful. The 18" wheels set off the exterior. All in all, a great car. It really is a muscle car with a Phd. Also, even with the big V8, it still gets over 20 miles per gallon. Not bad.