After discussions with Jim Smith today regarding this topic, I will take further issue with Findoc's comments. The later version 2 series (the Trios anyway), called the "plus" included the new woofers, amps, and horns. The woofers in the 3 series were described as sonically the same as the 2 plus series but have an additional input upgrade to increase sensitivity. This, along with the line level input which is almost never used, could be upgraded but is not recommended as it does not improve the sound of the woofers. The high impedance horns have been used on all of the version 2 plus models. The web-site does not clearly identify the evolution of the 2 series, rather it compares only the earliest 2s to the 3 series. Again, should one desire, all updates from the 2 plus to 3 series are being offered but most are unnecessary. Jim Smith at Avantgarde would be the most qualified to explain these issues.