Well, don't rule out that there is a crack in your coax wire and that
until you run a new wire your reception will never be good, BUT, I just
put a nakamichi cd-400 in my 1985 380SE. I also ran new 13 gauge IXOS
wires to alpine sps-460a in the rear and alpine sps-080 in the front.
Sounds good (unless you're a bass thumper), looks great, and now I can
play CD's. Also cleaned up my reception a good deal.