While doing some research on rads for various Honda automobiles, I discovered that the following Internet sellers do not have a physical location in the form of a genuine Street address, only a PO Box address for some:

WORST OFFENDERS:
HondaZone.com -- NO physical address, NO telephone number, Email only

REPEAT OFFENDERS:
RadiatorBarn.com -- Telephone and PO Box, NO physical address
RadiatorExpress.com -- Telephone only, NO physical address
RadiatorWorld.com -- Telephone only, NO physical address
Car-Stuff.com -- Telephone only, NO physical address
ThePartsBin.com -- Telephone and Email only, NO physical address

TRUSTWORTHY INTERNET AUTO PARTS SELLERS:
The only two Mass Market Internet Radiator Sellers I know of that shows pictures of the location, has a physical address, and lists a Telephone #.are:

AutohausAZ.com -- Telephone, Physical address, Email
AutoPartsWarehouse.com -- Telephone, Physical address, Email

These are the results of my personal research looking for a radiator.