Internal engine coatings?

Coatings certainly do have their return on investment. It's up to the guy with the checkbook to determine the sensibility of them. I've been involved with builds that used thermal barrier, oil shedding, and lubricant film coatings. IMO, you get decent return on the thermal and oil shedding. The lubricants are more for "cheap insurance" that another part fails the engine can better survive it.