no all of the parking brakes are crap on the kappas, even with slotted rotors, upgraded pads, and all of the slack taken out of the line. theres just not enough clamping force for some reason.
there is a trick (not really a trick) to get more clamping force if youve done the above and still seriously lack clamp force. just compress the rear calipers and that should give you enough grip to park on an incline. for some reason the parking brake ratcheting mechanism inside the rear caliper freezes up so you have to compress the caliper it to loosen it up that mechanism. once i did this my parking brake worked 10x better, its still not as good as id like but its way better than before.
hope this helps.