I have heard, and like very much, various PureAudioProject sepaerks, including the Duet with the wooden horn driver. It did not strike me as being excessively bright. It is very vibrant and alive sounding, but not so bright as to be annoying. But of course, taste vary. A custom builder in my area cap spot speakers and amplifiers with Mundorf caps in them almost instantly. He hates how they sound. To him they sound thin, bright, and analytical. I am not as much against Mundorfs, but I did hear an amplifier where he replaced Mundorf coupling capacitors with Hovland capacitors and the sound was, to me, dramatically better--warmer, full (no thin and thread bear when it came to instrumental harmonics). Perhaps you could experiment with capacitors, something really easy to do with PAP speakers.
As for wires, if you are looking for less highs and a lush sound, look at Audio Note copper wires. Some might be a bit expensive, but they will sound less bright than most wires without killing the life of the music and making things excessively murky sounding.