Cold starts are noticibly much smoother. Can't beat the quality vs pricing - costs about the same as rotella t-6 synthetic blend but it's full synthetic and contains no detergents. You can get it from most big rig shops and buy it in bulk to save even more. Haven't had the chance to try any in the z yet (undergoing heart transplant) but with the recent discussions of people switching to a heavier weight oil, I just may.