Leaking exhaust manifold gaskets are a fact of life in turbos, so that's normal. The rust is probably from rain in the yard. But now is the time to do the work: a head gasket job while the engine is on the stand is a piece of cake. Opening the valve cover will give you a good view of the innards.

Do the head gasket (use a Felpro gasket), replace both front and rear seals (all four), the timing belt and the tensioner. Replace valve hushers under the tappets. Flush the oil pan and oil pump strainer and replace the gasket. This entire job should take no more than four hours. Your engine will last forever.