depending if you have an ABS setup or not.
i changed out for larger rotors/calipers (integra) fronts and rear discs (integra). Changed my MC to a 15/16 and my prop valve to 40/40. Since you are only upgrading the rear discs, you may not need to upgrade anything for daily driving since you already have the EX setup.
it is usually recommended that you upgrade the MC and prop valve to accomodate more fluid being pushed to the rear discs.