I've got an 04 with the JBL 10-speaker system. I have noticed some popping going on in the rears, and I was thinking of swapping out all the speakers (except maybe the sub, as it sounds like nothing will fit in there) for higher quality ones. Has anyone done this? Did it help? I've been searching here for a while and I don't see any discussions where someone has done this. Some have added a sub/amp, some have replaces the 6x9s, but no one has replaced all of them, including the tweeters. Anyone?