Microfarads- Nano Speaker using PS95 and W5-2053

Hello.

I'm fairly new in the diy world just found out about this speaker design and it looks great. I was wondering about adding a third PR in the back and if it would
benefit the speaker. Would this require any changes in the crossover or elsewhere? I could do an external crossover so size wise it could fit. Also I
know there's a V2 out but I like the looks of V1 :D