The answer to your question is no, not unless the turbo sits higher than the valve cover. Reason why is that not only is the oil pressure from the pump pushing the oil into the turbo but the return line is also a gravity feed to the oil pan. If the turbo is not higher than the return, it will cause the oil to back up in the line and eventually blow the seals out of the turbo!!!!

Another reason not to....

The whole idea of the turbo being oil cooled is for the oil to carry the heat from the turbo and back into the pan. From the pan it will go throught the oil cooler and back through the engine again.

If the turbo returns the oil back to the head, your defeating the whole idea of running an oil cooled turbo thus bringing heat right back into the head. This will be very ineffective an inefficient!