8) i have never heard of it, but most of the ones out there make some what dubious claims. if you read carefully you will find they claim "up to X% more" what ever they are pushing. the key phrase here is "up to", that means you can get that increase or less or even lose the item they are promoting. also be carefull about the ingredients they list as some will actually damage the engine in the long term, sometimes in the medium term as well. i dont use additives anymore. i use a good semi-synthetic oil and change it about every 3K miles.