If your using it in your 03 it shouldn't be an issue for your catalytic converter. The very new cars might be more sensitive....but truthfully, the main reason I can see for the supposed worry about the catalytic converter is the government has mandated longer warranties of emmissions on cars...
I was wondering if it was a good idea or not to try some Shell Rotella T 5W-40 oil in my Volkswagen with the 1.8T turbo gasoline motor. I know this Rotella diesel oil has a lot more anti wear additives.
Thoughts??????