So it's AN-3 line... That should be fine. I'm running the same setup I think on my car and I'm just fine. Garrett (and other) turbos have built in restrictors. The ball bearing turbos having smaller restrictors than the journal bearing turbos. Still, sometimes you need a restrictor, which you very well might. I'm not sure what size to use. I think if you search some you might find out.
It's a possibility the turbo oil seals have failed.