Skids
you got it!!

Dont forget:
- Confidence in your plane - You gotta trust it in the turns thru heavy traffic!!
- Right Fuel
- Right Prop
- well balanced spinner (run out at the end of the crank is vital to peak RPM increases) Not sure where YS stands with their tolerances, but many manufacturers allow a wide tolerance that effects the engin up to 200-300 rpms and even more in some instances.
The list goes on and on. A well prepped plane performs for all heats and assures you points. A poorly prepped plane (as Terry remembers mine in Victorville) will give big fat zeros.

There are so many little things that when all put together make the difference.

Your list hits the bulls eye, but I am certain there are even more things like, glow plugs and a great Tx etc...