bear in mind that altering the size of the master cylinder changes the behaviour of the brakes. Bigger isn't always better. Putting a bigger one on will reduce the pedal travel but you'll actually have to apply more force to the pedal to get the same braking effort as with a smaller cylinder. The bigger cylinder is better suited to using bigger calipers really, with a bigger slave cylinder area. If you want to reduce travel then the bigger one is good, just beware of the pros & cons.
