I think what most people miss , is that the engine component coatings by themselves generally do not make more power . A friend of mine used to be an engine builder for several NASCAR teams some years ago .... I got to see what was done to some of the engines and , more importantly , why .
The coatings allow you to do other mods that will increase power ... for example , if you treat the piston skirts ( no teflon ) , it allows the tolerances to be tightened up on the piston to wall . This in turn means the piston doesn`t rock in the bore as much and the ring seal is a little better . Is it a tremendous amount of power increase ???? No , but in the top levels of the sport ... every little bit helps . Another example is coating the valve springs to reduce friction between the inner and outer .... makes them run a little bit cooler and keep the tension more consistent and live longer . Coating the tops of the piston helps reduce heat transfer and keeps it in the combustion chamber ... it also reduces carbon buildup and keeps things constant .
They also coat the counterweights of the cranks with an
oil shedding coating to reduce the parasitic drag on the crank from the
oil .... and you wouldn`t believe the amount of time that has been spent on the shape of the counterweights ( Hint ... what shape is a rain drop ? ) .
Main and rod bearings are also coated ... doesn`t add hp as much as it is insurance that if the
oil film breaks down momentarily , you don`t lose an engine ..... and on and on .
On my engine , I have the mains and rod bearings coated and the piston skirts .... not for power , but insurance and longer life .
Ballpark to do an entire engine used to be in the $500 to $800 range .
Coatings aren`t just for engines ... I have seen as many as 15 center sections/housings in my friend`s shop for an oil shedding coating on the inside ... again , it allows them to do something else that adds hp . They also coat the ring gear and pinion ... for reliability, not power .
If you have your heart set on getting some coatings , do the bearings , valve springs and ring gear and pinion ..... it will be a reliability advantage .