I'm going to be running Valvoline NextGen 5w20 in my sister's 2005 Honda Civic. I usually run PYB 5w20 for a 6k OCI, but got some NextGen at a good price. How long should I run the NextGen? Her car sees a mix of highway and city driving, and is driven decently hard. The filter I use for it is a Purolator Classic.