 Back in the 90's, my wife & I bought a used '90 Q45, the first year of Infiniti's new sedan competitor to Lexus, BMW, Mercedes and Cadillac. All these years later, we remember that car with great affection - understated yet classy design, beautiful interior w. lots of room (but not too big), and for the owner who loves to drive, great suspension and ride combined with a world-class 4.5 liter V8 that loved to run. And all with Japanese reliability.Lately, we've thought a lot about that early Q. When it came time to replace my 150k mi. Mercedes E320, we chose a 79k mi. '02 Q45. The '02 was the first year of the 3rd generation, but everything about the earlier Q45 still applies. Best of all, the final series Q has no real weaknesses as a used-car buy; no air suspension to leak, no Northstar engine to fail, no complex electronics and no current dealers who hate to see an older Q come through the service bay. Our local Infiniti dealer treats my 14-year-old Q as if it were a new Q70.In searching for our '02, I discovered: 1) there are relatively few 3rd gen Q45s out there - Infiniti just didn't sell many new, and 2) most 3rd gen Q45s have accumulated over 100k miles. That said, I found a relatively low mile (79k) example about 100 mi. away w. great body/paint/interior and accident-free history. Service records are always a plus, but (sadly) not that common; a pre-purchase inspection is always a good idea, as is a search for customer (& BBB) ratings of the dealer you're buying it from.For the new owner of a used Q, the climate and audio controls on the 2002-2006 series require a bit of reading in the owner's manual, but are actually very logical (if not intuitive) and work fine. The interior design, especially the dash & center console, is both gorgeous and trend-setting; the current Q70 interior design is very similar. Large, supportive seats come complete with lumbar support for the driver & are the most comfortable of any car I've owned in 45 years of driving. That includes a healthy number of BMWs, Jags and Caddys.The Q45 was designed as a grand tourer in the European tradition - fast, comfortable & stylish transportation that can devour continents. Infiniti succeeded at a price that undercut their competitors by thousands. Although some regard the 3rd gen Q45 as somewhat quirky (headlight design, HVAC interface, transmission in permanent sport mode), the car's comfort, performance and space make it a true driver's car you can live with. You won't win any economy runs with it (20 mpg in mixed driving), and given the slightly numb steering, the Q is not exactly a canyon-carver, but it will get you there in a hurry with comfort & panache to spare. Those Gatling-gun headlights are the bomb, but be sure to follow the owner's manual suggestion to avoid turning the headlights on for very short periods; that apparently will burn out the ballast much faster, which is not cheap to replace (removal of the front bumper is required.)Maintenance is straightforward - just keep the 5W40 oil changed (synthetic, of course), put on a quality set of tires (I'm running new Pirelli P7s), and basically maintain it w. fresh coolant every 3 years or so, good brake pads and new engine air & cabin air filters once a year. And don't skimp on using recommended premium fuel - that thoroughbred 4.5 liter V8 will be much happier. Keep it clean & enjoy the fact that you own one of the world's great super sedans: the Q45.UPDATE: Six months in, I'm still happily driving my '02 Q45, albeit after investing some money to bring it up to standard mechanically & cosmetically. I decided to spend $200 at my local Infiniti dealer to update the transmission software to make the throttle more responsive; they also replaced the electronic accelerator pedal w. a new design. After the upgrade, the throttle response is much better, although the transmission remains prone to stay in a lower gear too long when accelerating at anything other than a leisurely rate; it's as if it's in permanent "sport" mode. I also had the dealer change the transmission fluid/filter ($100) & do a proper 4-wheel alignment ($90). After the alignment, the car tracks/feels much better now going down the road.I also spent $500 to have the front bumper removed & professionally refinished/painted; the original paint was wearing 80k miles' worth of scrapes & scratches. Other expenses since purchase include new Pirelli P7s, new brake discs/pads front & rear and a new cabin air filter.  UPDATE #2: Our Q45 has accumulated 13,000 miles of daily driver use in a year with zero repair costs & no problems. Average 20.4 MPG in mixed driving; oil consumption averages 1 quart/5k mi., which seems normal from everything I've read about this engine. Fabulous car, great value, glad I bought it.FINAL UPDATE (April '17): Sold the Q a couple of months ago! Fabulous vehicle, still highly recommended, just too much car for a daily driver. Replaced it w. a 2010 VW Jetta. :)