I think it is important to realize the heat effects everything. The thinner air really effects engine and prop performance. You will notice it can effect your needle settings as well. As the day goes on, you will start to lean out. Maybe not so much with gas, but definately with glow. After competing for the last 18 years in high performance events like CL combat, RC combat and Pylon racing, it is important to note this.
I have found that engine and prop performance suffer even more than my wings performance.