Crossover upgrade capacitor question

For loudspeaker use, my opinions mirror Undertow's.

Wavetrader
don't forget that your option is not just 2x8 or a single 16.
A 12mfd and a 4mfd would also work.
For that matter, 16x1mfd gets you there, too, though space probably won't allow this. Anything that adds up to 16.
My Magnepan X-over uses 4 caps in the tweeter totaling 22mfd.
The smallest is a 0.1mfd bypass.
If/when I rebuild them, I may skip the bypass and go directly to the value, the combination depending on whose caps I choose.
One other minor point. Caps have a build tolerance. A 16mfd cap of 20% could be anywhere from 12.8 to 19.2mfd.
In the class of component you are thinking about, 5% is more common while I have seen 3%.
It is probably also possible to buy 'hand selected' parts of measured values.

BTW- Michael Percy will match his products to 1%(or closer) for you, which will keep your crossover points equal. Most high-end caps are manufactured with a(typically) 5% tolerance(or better) to start with. (http://www.percyaudio.com/Catalog.pdf)