I'm sure there was a note from his holiness Bob about tweeters. Something about selecting one with the most neutral presentation, smoothest off axis response and freedom from resonance & breakup.
Other manufacturers use carefully selected 'cheap' tweeters to great effect.

Mark
G68, baby Genelecs, Humax Foxsat, Oppo+Vanity93, Toshiba HD-A35, Pioneer CLD-925 + Meridian 519, various other random bits and bobs
Got a black G08.2 you want to sell?