[Tommy]

If the pedal feel and stopping ability of your current setup is OK for you, then new parts with the same geometry should be fine too. In other words, if you can lock the front brakes in an emergency stop now, getting a larger disc will not help you stop any better. On a track where the brakes are used heavily and cooling is a major consideration, bigger brakes make sense, but not for "occasional spirited driving." . . . During heavy braking the front brakes provide about 70% of stopping action. As long as you have a brake bias adjustment, I see no need to change the rear brakes from a performance perspective.