i think it was mentioned elsewhere, but specialized used niti tubes on the rockhopper in late 90s of which there is one on ebay uk right now. the richey niti bike was bottom of the range ( ) when the p20 and plexus used wcs tubes made by dedacciai so maybe that says something, but ive never ridden one.
the specialized using that tubeset were actually lighter weight frames than the specialized M2 frames of the same era. 1 of my mates wifes has the rockhopper comp, grey/black bike.