I just installed a new radio/cassette in my '87 Westy.  Since it didn't have
a radio when I bought the van, this was the first time I heard the four
speakers that were already there.  To say the least, I wasn't impressed.
What can I do to improve the overall sound?  Are there any decent 4"
speakers that can replace the existing ones in order to get more bass?  Is
it an easy job to replace the rear speakes with 6" speakers?  I don't want
to have to put big speakers under the bench seat like some have done.  Would
adding a subwoofer improve things?

Would be interested in how others have solved this problem without having to
spend a fortune.

Gerry