Ultra copper is usable as a gasket material for damn near anything on a car except for intake seals and turbo related stuff...you can use it for exhaust stuff like O2 sensors, but the footprint itself I think gets too much heat from the turbo to last.

You may be able to get away with it, but Permatex says it is only good up to 700*F. If you cant get a precut gasket, then its worth a shot