I agree with jessop in post #104, as far as similar syntax, especially Barraqué.
With sanantonio, what he said above is a main reason I like Boulez. He seems to use categories of sound, as in plucked strings (harp, pizz strings, guitar), struck mallet instruments (vibraphone, glockenspiel, marimba, xylophone), sustained sounds (strings, woodwinds), and it seems to be based on timbre, which was derived from electronic sounds and later IRCAM spectrographic studies of instruments.
I associate this "exotic" instrumentation with Boulez, and I think it can be heard in Messiaen (Et Exspecto, 7 Haiku) and Takemitsu (A Flock Descends, Quatrain).
There is a "jazz" Boulez ensemble recording, using a plucked stand-up bass and electric guitar, a la "jazz." It's here, for a penny: