John's HiVi project is highly recommended. Me, I went with the Tangband W3-871 a month ago, partly because I didn't know about the B3S at the time. The ELF's are very simple 0.1 ft^3 ported. Sounds good "naked" and even better with a notch filter of R=6, C=6, I=0.5I think both the HiVi and TB projects work out to be the same cost. The HiVi drivers are cheaper, but requires more filter components.
Gar.