Another brake issue

I am used to great brakes and XJ's suck. So this is what I did. I have Currie 9's front and rear, Explorer rear disc's, 06' Sport Track front with EBC pads. Was not totally happy so this weekend I took 2000 WJ master and booster, Modified the Rod to be the proper Length. When you drive normal the brakes are awesome, you barely need to use any brake effort just like a New Car!!! but when you hit the brakes real hard it seems like the pedal gets real hard? not sure whats up, maybe the proportioning valve. Any Ideas maybe its OK and i am just to picky.