there ar a couple of 2004 malibu's. we have a 2005 malibu maxx lt (200 hp v6) and are very pleased with it. the maxx is built on the saab platform, the wheel base is about 4" longer that the malibu but the maxx is a couple of inches shorter. it is fun to drive at hwy speeds on twisty roads. the maxx is a 5 door (think sports wagon). with great front and rear seat head room, comes standard with movable rear seats that recline and fold down. with the rear hatch open loading big bulky items is no problem. there is also a standard moon roof over the rear seats.
the 200 hp v6 works well and gets over 30mpg hwy. it's not so good in stop & go traffic (gets between 18 and 24).
the maxx received a 5 star safety rating, has 4 wheel disk brakes that are anti-lock and has traction control. 16" wheels are standard.
the best option is tilt/telescoping steering wheel, adjustable pedals and power drivers seat, (allows comfortable seating for my 5' tall wife as well as 6' + men. (did i mention front heated seats)
the malibu maxx had had only a few problems, one involves the steering system, it clunks and there have been a few problems with the panel on the back of the front seat (poor design).
we bought ours used and have owned it almost two years, we report no problems and continue to enjoy driving it, and load it up when we go to our rv site.
hope this helps