Well then, I shall have to keep this in mind after I put that amp put in. And since the car was designed to have components up front, I intend to get a pair.

So far, I haven't noticed any terrible amount of distortion in the midrange or bass frequencies, which happen to be the frequencies that sound better from the rear speakers, even at the highest volume I use on the CD receiver. I expect it will be cleaner with an amp. The only real problem I have is the plastic panels (especially the rear deck) vibrating with the bass.

So after the amp, I'll want to stop that rattling from the panels in the rear deck and the doors, and then I shall give thought to a sub. But only if and after I notice unacceptable distortion from the 6x9's.

Thanks goes to Tony and others again, for teaching me yet another lesson about car audio.