I've been experimenting with the following upgrades on the Trinity Punisher which is allowed at the club in my area:

1) Titanium screws marketed to increase RPM by 250+
2) Aluminum timing ring
3) Team Spec Ultra High Torque Rotor

I didn't measure each individual change separately but I installed all these upgrades for a friend, and folks were swearing he was running a mod motor in his car, ha!

Not really sure how to quantify any of these things without some sort of a torque analyzer (which I don't have), but I can definitely vouch for the performance gains I personally saw, the biggest increase in performance was the rotor, I am running the aluminum screws and timing ring in my motor which help boost performance a little but nothing like what I saw in my friends motor with the upgraded rotor... holy smokes!