Should I make any change to the thermostat?
What thermostat do you have in it now? For the record, I'm not a big supporter of lower temperature thermostats, and lower fan operating parameters, to fix cooling issues or to help your car run cooler. Before I get into why , if you have cooling issues (running hot) I'd rather see someone find the source of their issue and fix it.
Running at stk. engine temperatures and using a stock thermostat is NOT a bad thing. Trust me, I have close to 300k miles on my car, and I use stk. cooling fan settings along with an 195 degree F thermostat. For some strange reason people get the impression their cars will melt to the ground if they run at stk. engine coolant temperatures. I wonder if that impression came from the internet.
If you want to make the "most HP" from your setup, you'll need a hot engine, let me say it again, you'll need a "Hot Engine" and cool, cool, cool inlet air into the combustion chambers to make the most efficient HP. Yet, I see people trying to do the opposite. Cool engines and cool or hot inlet air temperatures is not the recipe for making the most efficient HP in a street car.
Combustion chamber temperatures are in the thousands, running 20-30 degrees cooler in coolant temperatures is not even worth talking about. The 20-30 degrees is not linear, meaning your combustion chambers temperatures will NOT drop by 20-30 degrees F and will have no major effect on engine performance.
In closing, a hot engine for best for cylinder sealing, cold intake air is best for power making, and oil temperatures in the range it was designed for, is the best protection. Sorry for the long rant, I could of left my reply at "What thermostat do you have in your car now"?