Probably you already know some of this stuff. If not feel free to have a read:
http://www.diyaudio.com/forums/parts/151392-best-electrolytic-capacitors.html
http://www.diyaudio.com/forums/parts/259375-panasonic-fc-vs-nichicon-gold-preamp-power-supply.html
http://www.diyaudio.com/forums/parts/171907-elna-silmic-ii-elna-cerafine.html
http://www.diyaudio.com/forums/lounge/232600-audio-grade-capacitors.html
You'll easily find the datasheets to compare FC, FM and FR. The newer FR
have superior specs in some points regarding ESR, ripple current and lifespan.
http://www.diyaudio.com/forums/parts/151392-best-electrolytic-capacitors.html
http://www.diyaudio.com/forums/parts/259375-panasonic-fc-vs-nichicon-gold-preamp-power-supply.html
http://www.diyaudio.com/forums/parts/171907-elna-silmic-ii-elna-cerafine.html
http://www.diyaudio.com/forums/lounge/232600-audio-grade-capacitors.html
You'll easily find the datasheets to compare FC, FM and FR. The newer FR
have superior specs in some points regarding ESR, ripple current and lifespan.