If you have sufficient freedom of placement, you can do fine with your 2 functional JL subs.
There are different types of bass (which can affect the entire presentation), and can provide a different kind of enjoyment for different genres of music.
If you have enough room, I would get another pair of a very different type of subwoofer design & ethos. Swap between the 2 different subwoofer pairs for some variety in listening.
Adding more of the same sub and sitting around with the same sonic signature all year sounds a bit boring, don't you think? It is also the reason some guys may have several pairs of speakers, different electronics and so on.
You are stuck with the same woman all year for years on end...might as well have some variety with the music and equipment (at the least)...
Variety is the spice of life.
Good luck

