Barums are 'OK'.. I have them on the front on they've got a tendency to slide easily when pushed in greasy conditions, or I'm overdriving
550 for the 4 is a decent price for the Barums, or you could always hit up the local part-worn place.. I don't want to start a debate on the 'safety' of part worns as it's been done before, but there are plenty of decent places about (my mate runs one).