The 9's are a notorious load that dip below 1 0hm. Many amps will see that as a short and automatically shut down . For amps, consider Aragon 8008 and Palladium monos or Spectron. There is no such thing as overkill for those speakers but, as your friend will confirm, underkill is easy and more likely to be fatal.
Other than that, the Kappa 8's are an easier load, shorter, lighter, and don't sacrifice much of the bass.
Other than that, the Kappa 8's are an easier load, shorter, lighter, and don't sacrifice much of the bass.