I know they have scented additives that make exhaust smell like cherries and fruits but do they have any for coloring?
save your money on additives . practice better driving habits take off slow and stop slow . let off the gas and coast when you come up to stop . the more you do it the better your mileage will get I can get a couple miles better just by doing this . this will also make your brakes last a lot longer
Exhaust coloring would involve combustion, and an additive that creates colored soot would prove detrimental to an engine.
NO. However, high quality lubricants in engine, trans and dif might help. Good tune up and, if your mechanically inclined, hydrogen injection, will make a difference.
