The specs on the 350 are not totally updated as Axiom has not completed lab test in an anechoic chamber on the new sub. This new sub has a Dynamic power supply which the older model did not. In Alans blind testing the new 350 did almost as good as the 500, and beat the other two 3 letter brands. \:\)
Unless I missed something, I don't think the 500 was included in Alan's test. It was the original 350, new 350, and a 3 letter brand.