* rjk, thanks for the response. But you failed to mention whether you just add Sea Foam to the tank or whether you direct-feed it into the running engine. I think you mean, implicitly, that you direct-feed it, but I'm not sure.
* And, if you direct-feed it, how do you decide when the engine would benefit from the process? Or do you have a predetermined preventive-maintenance schedule (and the service happens even if they're running great)?
* So you've used Sea Foam primarily in the B23 series Volvo engine? Any B23FTs in that group?
* Which Mercedes models have you direct-fed Sea Foam, and how did that turn out (symptoms before, engine reaction during direct-feed, and performance after)?