well i know for a fact that the Subaru WRC car has an electronically controlled center diff that unlocks the rear as soon as the E-brake handle is pulled, as far as the hydraulics go you are totally correct. Hydraulics offer 3000 psi of pressure where with mechanical linkages you will maybe see 700-1000 psi of brake pressure. Personally i don't want RWD, if i wanted RWD i'd get a corvette then you get the best of everything for the money. I love my car the way it is.