I have to state something I have noticed. I have done 2-3 trinity punisher, 13.5’s, and I swapped out the timing ring and screws and shims with nonmetallic. On neither motor did we pick up anything kv or rpm wise but the amp draw did drop a tad. Now on something with a standard rotor, I have seen 150-160kv and 1500 rpm gain, that was on a motiv 17.5. My theory is on the punisher, the rotor is already so big and so strong that the magnetic interference from metal screws is. It enough to change or warrant the upgrade to aluminum.