I recently acquired a 1999 Honda CRV LX and the sound system sounds lousy. Can I get substantial improvement in sound quality simply by changing the front speakers or to gain a significant improvement in sound will I have to replace the head unit as well. How do I remove the front speaker grills? Do I simply put a screwdriver in the slot below the speaker grille and pry it off or is there some secret I need to know about to remove them without damage?