My speakers are JPW P1, 8 ohms, 8" woofer.
I am curious to know:
What are the best speakers out there which are 8 ohms and 8" woofer (and less than US$700/pair)?
You could bring them up to the later spec of the JPW AP2 by lining the insides with Dynamat. There are cheaper alternatives that are just as good (Noico is a lot cheaper in the UK). You could also experiment with stuffing. Fibreglass is by far the best, but obviously not nice to work with. I know there's a certain spec of rigid fibreglass that's supposed to be the best, but I can't remember what it is. Rockwool is probably second best.
Add a good, sealed subwoofer, and I'd imagine you'd have to spend a fortune to beat the JPW P1. I've owned and heard enough speakers to know that they punch well above their price class.