If it sounds too good to be true... it probably is.
Some time back I had an old RG250 - 2 stroke motorbike. It came time to sell but unfortunately the engine was getting a bit shagged - probably piston slap from worn bearings. Anyway it was rather noisy so I stuck some thick (crap) oil in it and hey presto! it was worth an extra hundred quid. It was still knackered but diidn't sound nearly so bad.
If this stuff has any beneficial affect at all I bet it would only be temporary. And I would worry that it may be building up in all the wrong parts as well.