My first time using the Royal Purple HPS 5w30 in my 2012 Audi A6. Until now I was using up my stash of Royal Purple 5w40. With 5w40 the car ran smooth and quiet but it had a slight top end valve train ticking and also a little clattering on very cold starts. I've had the HPS 5w30 in the sump for 2 weeks and both the ticking and clattering are completely non existent. Thus the oil runs a little smoother and quieter than the RP 5w40 which was surprising because 5w40 ran super smooth and quiet in its own right.