td05-16g from an impreza can flow upto 320-340 on a 4e, but all down to a decent ECU and a good map. at 1.5bar on a td05 you should with a okish tune see from 290 to 300bhp area.. but td05s can run 1.7 if you want a power figure, and then ran a little less boost on road for turbo reliability. 1.5 is good boost for a td05, 1.2bar is minimum it likes otherwise you may as well go smaller turbo.. l