I have no speakers for you any longer. I sold mine about six months ago to help finance a pair of Steve's FRX drivers. Yes, I built a pair of ZOBs a year ago, and mounted the Tang Band speakers.  There was a waiting list for the FRX speaker. Rather than wait, I bought the TBs from Parts Express and mounted them. I was shocked at the outcome.
First, the speakers actually worked. Next, they worked wonderfully! I promise that you will not be disappointed. The speakers have a marvelous voice, and express detail and dynamics like few others I have been able to afford. The FRX seem to smooth things out at the high end. Are they worth it? I guess maybe, but I think a sub-woofer adds more.
I compare them favorably with my other speakers, a pair of Gallo 3.1. The gallos have a special ribbon type of driver for the highs that makes them as transparent as electrostatics. In this area they beat the ZOBs. However, I pulled the Gallos in favor of the ZOBs and then employed the bass speakers of the Gallos as a sub system for the ZOBs. I have never enjoyed my music so much.
The are amped by a pair of Decware Super Zen Triodes. The result is a richness and as detailed presentation as I've ever heard, balance from the lowest lows to the highest highs. I tell you all of this so to prepare you for the pleasure your building experience will ultimately bring. I hope you can find a pair of TBs for your project. Keep me up to date on your progress, if you think of it.
Lynn Davison

Bump in' it up.  No one out there upgraded drivers to the FRX2 and wants to unload their 1808's?