No I have not heard of them before.... Be careful though there are a lot of oil additives that do not work and will cause harmful effects to your engine in the long run.
There are 3 things in my opinion that you need to look for before getting an oil additive.
1. Make sure the product has had testing done and shows positive results. (There is no harmful effects to the engine in the long term)
2. That the product has documentation
3. The product has been SAE approved. It is expensive to have done that is why most companies/products have not had it done or they just dont work. This is what truckers look for. Because only a small amount of products that go through the testing unless they work they wont pass. So the biggest one to look for is being SAE approved.
If you go to
http://www.oiladditive.tagzap.org they give you tips on using an oil additive what to look for, how you can benefit from it, etc. The product that they recommend has all 3 of these qualifications. I have seen a lot of oil additives and I definitely recommend using purrrform. I am using it and am saving over $288 and increased my gas mileage by 12%