You've probably already brewed this, but anyway...
whitelabs says this about this yeast: "Provides a complex, oakey ester character..."
If you want that oakey flavored ester in your porter you would be better off to pitch the pack without the starter, slightly underpitching will give more esters. If the pack is old, or you don't want the oakey flavors, make s starter.
If you've brewed already, what was your decision? let us know how it turned out