Whatever you choose, don't spoil the brew by adding an additive. Its probably already in there.
My better half has a 97 Escort with a CVH engine. Its into 90 odd
thousand miles now and apart from when Ford serviced it for the first 2 years, i have always oil changed it every 10,000 mileswith a 10/40 semi sythentic. Recently I had to swap a leaking rocker cover gasket on it and was pleaseantly surprised to see how spotless the engine internals are.
No doubt most Lexus Engines will be the same.