Car audio guy here....

Why would you say that? My 64 Barracuda is 100% stock. Minus this little Gem http://www.classiccarstereos.com/category/Secretaudio-SRMS.html
Along with a 6x9 dual voice speaker in the center.

Now my 65 Signet is a modified, with full custom radio and power windows!!

Gotta have tunes man!