IIRC Rotella hardly has any ZDDP compared with the original formula that was available 6-7 years ago. The Aircooled guys loved the original formula but still use it because it still is higher than anything else on the market and the extra detergents really help the non-filtered AC'ed Volkswagens. A few of the real anal folk (mostly Porsche guys) buy some concentrated zinc additive that's super expensive to add to every oil change, right before they send their old oil off to a lab to be analyzed (LOL). Whatever floats their oil boat.
