I'm sure they do. It's another way of exctracting money from customers.

Some more feedback about this?

Thanks

Had this done on my wagon 3 years ago, really out of desperation trying to cure a cel; it didn't cure it. Hard to say if it ran better too. Shortly after, I had my injectors pro cleaned, and that cured the cel, and the car ran fantastically. So if you are over 60000 miles, that's were I would spend my money, given how important spray pattern is for turbo cars

I had a smiliar treatment (carbon clean) on my ST220 and by a startling co-incidence the main bearings on the always warmed and cooled, 8 year old sub 60,000 mile engine (twice yearly oil changes) went during the treatment.
So, I'll never have it done again.
Personally I think the old way to get rid of carbon build up is ultrasonic for delicate parts and elbow grease for everything else.