Complete Fuel System Cleaner: Is it safe?

[JerseyJeff84]

I know this may have been asked before, so I apologize, but my '10 Yaris Sedan currently has 20,000 miles on it, I happened to stumble upon GumOut Fuel Injector cleaner and used it back at 17,000. The bottle says to use every oil change or 3,000 miles, and while at Wal-Mart last week, I happened to see STP Complete Fuel System Cleaner which claimed it targeted four different areas as compared to GumOut just being for the fuel injectors. Being a complete product, it was double the price, but are these safe to use?

I'm somewhat OCD about keeping my car tip top shape and don't want to mess up something that isn't "broke." The car handles and drives excellent, I just look for little inexpensive things to possibly help it. Thanks in advance.