I don't agree that upgradng rear brakes is a waste of time. I do agree that the fronts do most of the stopping but upgrading the brakes can change this proportion. The trick is to upgrade but not to the point that the rears lockup. Brembo's have a split between front/rear where the rear have a larger proportion split than other systems used on Subaru' s. This thread shows why upgrading rears is important.
http://forums.nasioc.com/forums/show....php?t=1265631