IS there a difference in the master cylinder of a Classic compared with a WRX ?
My friend and I have the same Big brakes (AP), and his pedal has much less travel then mine, there is NO air in my system.
It's just that his pedal is harder and with less travel, my pedal is more easy to "regulate" slight braking, but has more travel...

 

Has your mate added anything else to the brakes like goodridge hoses or support bracket for the master cylinder to prevent it moving under braking? Cause these two items make a great benefit.

 

We both have those two items 360ste...
I was thinking more in the direction of the brake booster (single or dual step) or adjustement of brake pedal (but you have to know how much you can adjust then...)