This is a matter of opinion, but I think it is a good idea to ceramic coat the piston tops, valves and combustion chambers. I also like to teflon coat the piston skirts and rods.
Here is my reasoning - while the coating companies will tell you that you can make more hp when you control the heat and reduce friction (a good theory), I do not think that is what makes it worth doing. If you coat everything and something goes wrong, you are less likely to severly damage your motor. For example, if you go lean, etc.
I have seen a lot of the domestic guys that run really big N2O shots doing this regularly now. They claim that when they break their motors (always happens with that level of N2O eventually), that it is much less severe and much less expensive if everything has been coated.
My .02.
Here is my reasoning - while the coating companies will tell you that you can make more hp when you control the heat and reduce friction (a good theory), I do not think that is what makes it worth doing. If you coat everything and something goes wrong, you are less likely to severly damage your motor. For example, if you go lean, etc.
I have seen a lot of the domestic guys that run really big N2O shots doing this regularly now. They claim that when they break their motors (always happens with that level of N2O eventually), that it is much less severe and much less expensive if everything has been coated.
My .02.