Just replaced my front speakers with a pair of Sony X-Plod XS-J1621 120W speakers plus baffle boards (made of some kind of sound deadening material).

Man, what a difference in sound, I always knewthat OEM speakers are crap but seing those I was afraid touching them as they seemes to fall apart when just looking at them...they're just made of paper-like material!!

I just recommend everyone to go for that step and replace speakers.
Next step would be the rear speakers.