I know from past readings the ZDDP/catalytic convertor poisoning issue is controversial, but, given that federal emissions standards mandate that the auto manufacturers warrant catalytic convertors for 8 yrs./80,000 miles, there could be some "hot" car owners when they get the news the premature death of their convertors' warranty claims are denied. (regardless what really caused the fault) Use of a non-API approved oil might just be the ticket to that denial. There is evidence on both sides of this issue, so an arbitrator or judge will have a tough call to make. Someone will be disappointed when that happens on case-by-case rulings. You can bet where the auto manufacturers' legal guns will be on this issue, and they'll have their employers' policy of not using high-ZDDP motor oils as factory fill to back them up. The API and ILSAC won't be far behind. And, where will ExxonMobil be in these cases? Probably out of sight, but if forced to testify, I would imagine the company would claim that the "R" stands for closed-course "racing" - not "street". Like it or not, the API (gosh, isn't that organization funded and manned by oil company people?) is fast becoming a quasi-extension of the EPA.