Any pour in oil additive I have ever seen in my 25 year automotive career are merely thicken the viscosity of the oil. Use a thick oil, like a 20W-50 and that rod knock also would have stopped. There's no magic. You could buy bulk 20W-50 oil, put it into oil bottles labelled, "The-Truth81 Magix Elixir Oil Additive", and sell it for a good profit I suppose.
Also, using any pour in oil additive will void the warranty with the oil being used in the engine. The point I was making with mentioning that many new car manufacturers stating using pour in oil additives is not recommended and can void the warranty, is that is not exactly an endorsement for pour in oil additives. Using any of these pour in oil additive products upsets the chemical balance of a motor oil that an oil company went to great lengths to formulate and can have negative and unplanned affects. If a cake recipe, (an oil formulation), called for 2 eggs, (additive chemicals in the oil), and we put in 2 more eggs to make the cake, "better", we'll end up with a cake, (oil), that isn't as good as what it originally was.
i have never changed the oil in my car without a qt of lucas. ever since my 230k mi t-bird. had a rod knockin, put in some lucas, ran till 270k mi and motor still ran strong. just ended up rippin the rear out being stupid. come to think about it maybe i should have put lucas in the diff to!?!? lol i use lucas religiously. never heard anything bad ever happen from using it. plus i work at the dealer so... and the warranty was history forever ago n e way. you know like 90% of all those bolt ons can void the warranty to. so its safe to say i am the warranty now. lol but it really comes down to personal pref. so what ever floats your bout i guess.