Audiophile question

[MHLIGGINS <MHLIGGINS@aol.com>]

     From past reading I know that some of you folk are serious audio types,
and I think one or two work at audio stores.  I need a bit of information.
     My son wants to be able to "pump up the volume" in his '88 5KS.  He has a
Sony "something 350" with extra bass stuff available on a 4 position switch.
If he adds much volume, the stock speakers (surprise) distort.  This afternoon
we tried a pair of Panasonic 3 ways in the back of the car.  They are 180w/50
w speakers.  They also distort, and did not provide as much bass "thump" (is
that the technical word here?) as the pure stock speakers.
     So, when the little goobers are cruising down the alley behind the house,
rattling the windows in our house, are they getting distortion?  Is that
considered the price that has to be paid for volume?
     I figured that a mid-range Sony cassette player (30w or 35w per channel,
4 channels) would not be able to over-drive a pair of speakers that are
supposed to be higher rated.
     So, someone please bring me up to speed here.  Or send me to a website
that puts it in basic english.  Or tell me what to read.
     Many thanks.

     Later.
     Marty Liggins
     Imperial Potentate, Bucksnort Quattro Club (Un-Inc.)