2001 Kia Optima engine matches

I was wondering if someone could tell me what year engines will fit a 2001 Hyundai Sonata with a 2.4 4-cylinder. I read that a 1999-2001 Sonata will fit as well as a 2001 Optima, but I also read somewhere else that a 2001-2004 Optima engines are interchangeable. I was just wanting someone to confirm that a 2001-04 Optima engine will fit my Sonata before I buy something I can't use. Thanks!