i bought formula activa disc brakes for $25 each (i know i should have spent more and gotten avids) and the stopping power is only slightly better than v-brakes. i think if i buy new disc brakes i have to buy a new wheelset because i stripped 1 or 2 rotor bolts on each wheel by using an allen wrench(i thought it was the right tool at the time). any way the question: how can i improve the performance of these brakes?