Electrolytic capacitors (regardless of the manufacturer) produce much more distortion than polypropylene, for that reason I never use them to set a time constant (like in a crossover). They are pretty much irreplaceable in power supplies because as you say they are available in much higher values. It is also possible to use them to AC couple the signal, as long as they are grossly overrated they will not affect the signal within the audible frequency range.
There is nothing wrong with using multiple capacitors in parallel (you just add up the values), unfortunately this doesn't apply to the voltage rating so each one of the capacitors needs to be rated in excess (usually double) the maximum output voltage (RMS). The other advantage is that you can measure each capacitor's value individually and come up with a combination that get's close matching for left and right channels. All you need for that is a pretty basic multimeter.
I'd advise taking a look at something like the Wima MKP 4F before shelling out on the boutique types.
There is nothing wrong with using multiple capacitors in parallel (you just add up the values), unfortunately this doesn't apply to the voltage rating so each one of the capacitors needs to be rated in excess (usually double) the maximum output voltage (RMS). The other advantage is that you can measure each capacitor's value individually and come up with a combination that get's close matching for left and right channels. All you need for that is a pretty basic multimeter.
I'd advise taking a look at something like the Wima MKP 4F before shelling out on the boutique types.