I like Chevron Supreme w/ Techron, 92 octane.
Although a local company Tesoro sells some specialty stuff, 101+ octane.
But I don't think the Zetec was really designed with 101+ octane gas in mind, so I don't see the need for it.
But the muscle car guys love it.

1997 GL Sport MTX,
Soon to be the fastest proven Zetec around.