I had fitted the 320 mm EBC rotor years ago along with a braided line with the stock master cylinder.
Current set up is a DR650 wheel/axle with DR EBC 320mm rotor in RMZ forks with a RMZ450 caliper adapter and master cylinder.
Custom built braided line.
Rear is a EBC rotor and Procycle braided hose.
Procycle SM wheel set.
Dirt spec is RMZ450 front wheel with a stock RMZ rotor and DR rear wheel with a stock rotor.
With the as delivered DR brakes,braided brake lines made the biggest difference followed by different pads.
The braided line meant you could use the stock front brake to its limit due to the feedback delivered which was not possible with the stock long rubber brake line swelling under application.