I decided to upgrade the sound system in my 1999, gradually.  Last year I replaced the amp which helped.  Today I replaced the radio with a Pioneer DEH-P5900IB.  I was pleased with the results but the AM reception is terrible.  I know that this seems minor but I use AM for traffic reports, news and sports.  The installer told me later that this was common with aftermarket radios.  I guess no one under 30 listens to AM anymore.  Any thoughts?  Help.  
I was also thinking about replacing the speakers in the instrument panel but getting ones to fit the speaker grille was going to require some modifications so I decided to pass for now.