Those are the hoses to the oil cooler. The rubber lines carry coolant only, so just drain at the valve pictured. You'll notice that the oil filter sits much further back on the turbo cars. There is an aluminum adapter that screws into the block, sweeps back, meets the oil cooler, and then holds the filter. If you're leaking oil, it is probably either the o-rings in the cooler (see the FAQ for the bizarro socket sizes) or your filter gasket. Oil from leaks or oil changes drips down onto those hoses and corrodes them.