Anniee 
2003 Nissan Altima Sedan 3.5 SE 4dr Sedan (3.5L 6cyl 5M)
Beware the Catalytic Converter
 Originally car was great-looking and drove beautifully.  Last year started to drive rough and didn't pass emissions.  Had to pay $1200 to replace 4 valve cover gaskets.  Was driving on major interstate at 60 MPH in the fast lane and the car suddenly stopped dead.  Scariest moment of my life.  The dealer is saying pay $1300 for catalytic converter.  This apparently a HUGE problem with Nissan Altimas.  Get yours checked before the 8 yr. 80,000 mandatory replacement expires, because Nissan won't replace if you are at 80,001.  Disappointing at best and no longer have confidence in car.