I've never heard the Pass Xover, but I have heard an excellent 3 way Marchand on the 20.1's (sub attached to the active and crossed over at 34 hrz) with Pass amps on the bottom and ARC tubes on the top, and that was one of the best sounding systems I have ever heard.
Of course I need to say that the analog set up was top notch as well so.......
Of course I need to say that the analog set up was top notch as well so.......