Just a note to those thinking of making the change (which we think is very worthwhile)
Its a good idea not to change the value. Increasing the value to get more bass may cause the low frequency cutoff to go too low- lower than the power supply low frequency pole for example. This can result in low frequency instability or maybe just flabby bass.
Your 2nd best bet so far is the Mundorf, but if you are using the cap in an output section, consider that in due time most paper and oil parts will develop a small amount of electrical leakage, which can have disastrous effects on the bias of power tubes!
The following applies to all Teflon caps:
Don't try to cut it close on the voltage ratings. Our experiences with several Teflon types is that is asking for the cap to short! Leave plenty of leeway for the voltage rating, and don't forget that during warmup the voltages across the cap will be equal to the voltage of the unloaded power supply!
Finally, do not give the part a lot of handling. Teflon does not 'cure' like polystyrene and polypropylene, so handling the part can cause the dielectric to pull away from the ends of the parts, changing its value or even shorting it. Once in circuit they are fine.
