There was a posting on the Bott forum about a new crossover that's being developed for the Straight 8. Until more information is available on this upgrade the best improvement will come from implementing the currently recommended crossover upgrade with the 1.5uF cap and the resonance filter in the tweeter section. It's a matter of personal taste, but I found the revised crossover significantly improved the sound by taming a 3K peak with the original design that I found very distracting. Information at http://www.bottlehead.com/straight%208/updated_straight_8_crossover.htm