Do the 520 conversion with a hard anodized aluminum rear sprocket when it is time to replace the chain and sprockets (DID ERV2 chain and AFAM sprockets). This will save some rotating mass.
Make sure you are high up in the rev range when you guys take off.
A full exhaust will give you the few extra hp up top. Should be able to get a good exhaust and custom map for well below $2K. Plus you can sell your slip-on to get some of that money back.
Remove your mirrors or fold them in for the race to cut down on wind drag.
Don't fill up the gas tank before the race. Have enough gas for the race and ride home.
Do you have a double bubble which will help you with tucking out of the wind?
I am not sure how much weight you lose with the 180 tire. It is narrower than the 190, but it is also taller.