THE brake package has been upgraded on the B4 with ventilated discs all around - 294mm in diameter on the front with twin-piston floating callipers, while on the rear they are 290mm in diameter with single-piston floating callipers. ABS (anti-lock brakes) is fitted as standard, with the B4 using a Bosch 5.3i four-channel, three-phase, four-sensor system. The new system has a higher frequency and bigger capacity computer control unit, to provide faster and more accurate wheel speed control. Changes to the brake booster have been designed to reduce pedal effort while retaining a firm, progressive braking feel - falling between the hard feel of the WRX STi and the softer feel of the Liberty RX.