Isn't it also a selling point with their fuel..chevron gas with techron in it??
I cant comment on Sea Foam, never used it.
Chevron does use the Techron (was known as Techrolene) in their gas but its a small amount for everyday use. The concentrated stuff is for engines where there IS a problem.
Shell has a simular additive as does Unocal.
Using the Costco Techron is probably good too but with the lower amount of active ingredient, youll have to do the math on what is the best buy. We use it on bikes that have a problem or as a every few months "booster shot".
Again, ours is one ounce per gallon, 15.00 per 20 ounce bottle.