Correction: Regarding the Bottlehead Straight 8 speakers I said "Their 97dB MTM drivers combine to produce an oveall efficiency of about 96dB". I meant to say their 87dB MCM brand drivers combine... One limitation of this speaker I didn't mention is the fact that it used $10 woofers and a $12 tweeter. A better choice would be the original Linus 1 speaker, which incorporates 12 of the shielded version of the MCM sourced Straight Eight 5" woofer and six $25 Silver Flute planar tweeters instead of the one $12 MCM tweeter used in the Striaght 8. Total cost for the drivers and crossover parts for the Linus 1 will be about the same as the $600 price of the Straight 8 parts, and you will get a better sounding speaker for your $600 investment.
But if you are willing to shell out $600, for just $300 more you can get a Linus 2 array kit which included 10 of the much better 5.5" Vifa TC drivers and 8 Silver Flute tweeters plus all the crossover parts. The bottom line is about $200 worth of drivers in the Straight 8 for $600 total msrp versus about $800 worth in the Linus 2 for $900 msrp.