Would the Deutsche Mark appreciate or depreciate If Germany left the euro?

Would the Deutsche Mark (DEM) appreciate or depreciate if the anti-Europeans managed to pull Germany out of the euro zone? Germany has a large external surplus and massive external assets; this would drive up the DEM if Germany left the euro; Germany has markedly higher production costs than the other euro-zone countries and is now losing export market shares: a return to purchasing power parity would therefore lead to a depreciation of the DEM if Germany left the euro. If Germany left the euro, the DEM would probably appreciate since there would be excess demand for the DEM due to Germany's external surplus and financial markets’ reaction to this exit. Such an appreciation of the DEM would worsen Germany's cost competitiveness problem even more, and this should discourage Germany from leaving the euro.