Nice earner!

IMO, there is no really good reason to use either if you use normal fuel found in the USA. I have had to remove injectors on several high mileage vehicles for various reasons and in each case I found them pretty clean with just a film of brown tarnish.

I doubt the $85 service is simply pouring a bottle in your tank unless they are genuine rip-off artists. Regardless, if you have good quality fuels, it shouldn't be necessary. I try something like this every once-in-a-while when I have a car with an issue I think it might correct, and then I use GM top engine cleaner as it's a much better cleaning agent (by far) than any other product I've used.

I doubt the $85 service is simply pouring a bottle in your tank unless they are genuine rip-off artists. Regardless, if you have good quality fuels, it shouldn't be necessary. I try something like this every once-in-a-while when I have a car with an issue I think it might correct, and then I use GM top engine cleaner as it's a much better cleaning agent (by far) than any other product I've used.