Generally, I trust stuff from lubegard.com.What kind of additives and chemicals would you run in the gas and oil?
LubeGard has lots of good stuff.
If you change the oil often enough, and use Chevron with TechRon Fuel System Cleaner, or anything approved by bobistheoilgy.com, you really don't NEED to use additives regularly.Is it even something to be concerned about?
However, whenever I get a new used vehicle in the family, I'll use
Bio/Tech Engine Oil Protectant - Lubegard in the motor oil with Group IV fully synthetic 0W30 ONLY
in cast the previous owner Toyoduhr'd the maintenance.
The rest of the ISSF will surely have plenty of good advice about how to prep the inlet manifold for re-installation, what sealants work best, etc.