Only reason I ask is I thought you mentioned kicks, and the last time I did a purely kick mounted enclosure the best I could get was around 2.5L (this was in the laser, which had a quite spacious kick area).
If you have another area you can get them in with that much volume available then that would be great. 20L may be a little overkill if anything - 10L (or even 8L) should be more then enough.
Bigger for an enclosure isn't always better for a given situation.













