2003 XB drive belt unique. factory part # is G0500.02A8R
you want the belt that does NOT end in the letter F but rather R. R is improved and superseded part #. they're not cheap and they're not plentiful but they're out there.
i would go with a James proven quality top end rebuild gasket set.
03-06 model years is JGI-17049-04-X there is a kit floating around out there that ends in W but lacks all the gaskets required.