Pull the drain tube off a little so the oil exiting the turbo will drip into it, and start the motor. Does it drain well or come out the sides? If its coming out the sides, see if it's still leaking while paying attention to how much oil you're losing (don't want to lose too much and run the motor dry). If it doesn't, then there's a problem with the drain. If it still leaks, there's a turbo problem. Shouldn't come out of the turbo as much more than a steady drip.
I don't think swapping to -3 will help if the restrictor is on the turbo itself (not on the engine). The restrictor should limit flow no matter what size line is feeding it.