Terry - both of these suggestions are good ones. The best thing for
the audio caps are film capacitors and for the low signal levels cheap
mylar film will do just fine. The improvement is mostly on the high
end of the audio spectrum where the response characteristic of the
electrolytics is very poor. I'm not so sure you would notice too much
of a difference with changing out ceramic caps. The bandpass switching
diodes can be problematic under high signal levels if they are standard
PN diodes and this is noticible on the R-2000 in the 6 MHz range if the
stations on 49M are strong.

Frank