I really do not want to spend more than $1000 on fronts and sub right now as this project took on a life of its own and budget got away from us. I got a great deal on the Yamaha ($250) and the NHT Superzero's are considered E stock and paid $60 a piece for them. As you can see I am not opposed to B stock or refurbished items.
This forum has been very helpful as I second guess my speakers.
Since you have those fantastic NHT SZ, why not just get 3 more SZ so that you will have 5 identical speakers for perfect timbre matching?
I would just hang all the SZ on the wall also.
Then get the Rythmik LV12, which is flat from 19Hz-300Hz. Just set your XO to 120Hz all around.
I actually currently set my XO to 120Hz with absolutely no adverse sound effects.
Nathan Funk recommended that I try setting my XO higher up to experiment. And it seems to work great.
When I had the SZ for over 10 years, I never heard any adverse sound effects when I set the XO to 100Hz either.