Boulez´ Parsifal = The reciprocal Wagnerian answer to Harnoncourt´s Figaro

"Well, it´s not like anyone would dare apply such extreme tempi to Wagner´s operas as those applied by Harnoncourt in his Salzburg Figaro?", is the common response to my lack of understanding of why Harnoncourt´s choice of tempi for his Figaro are that controversial.
(now, I am no frequent listener to Mozart´s operas to put it mildly, but I find his reading of the score the closest worth listening to I can remember having heard, with added poise and gravity resulting from his slower-than-commonly-used tempi).

And they are completely wrong, of course. The tempi of Boulez´Parsifal are much more deviating from "normal" performance practice than Harnoncourt´s. Boulez cuts about an hour of Parsifal, when he is at his fastest, which is ~25% of the total work lenghts. Both in his 1970 recording and in the Schlingensief Parsifal performances in Bayreuth 2004-5.

So my reaction to that? Well, it really is fast..no kidding..leaves me almost out of breath after the first act. But at the same time transparent and clear. Wonder what makes him prefer such a fast reading for Parsifal, which he didn´t in the 1976 Ring...
I am still going with Barenboim or Thielemann, though. Or Knappertsbusch.