There are alot of oils out there that just don't contain the higher levels of ZDDP that oils used to contain to keep flat tappet cams from going belly up. You can still get oils with enough ZDDP in them, but they're getting harder to find. The nice thing about the additive, is that you can just put it into your favorite oil. I bought the stuff and am using it in my TR3. Since I just got done with the restoration, I don't know how effective it is. I'll let you know in a few years! :laugh:
I believe it's the real deal, and feel that the extra bit of protection is worth the price and convenience. I have several bottles of the stuff on the shelf in the garage, right next to the bottles of oil.