Forget it its a waste of money.At least its cheaper than the other rubbish endorsed by that Quentin thingy off the telly!I'm sure with all his money he would just get the engine rebuilt.
It's probably some gloop like moly or something, which does actually reduce smoking, noise etc. BUT if you're engine has low oil pressure, smokes and makes strange noises the only cure I'm afraid is a strip-down and rebuild. No amount of gloop will cure worn out metal.
I have used similar stuff on worn engines and it does temporarily work, but as I said, a rebuild is the only cure.