Been using the dealer to get oil and filter changes all these years. They
use Castol oil and Honda filter.

I can get a better price on an oil change at a non dealer. A place that also
uses Castrol Oil. Should I absolutely request they use a genuine Honda
filter? Also, what is the recommended oil viscosity for a 9 year old Civic
that is going to see a winter with snow and cold? I was going to ask for
10W-30.

Thanks