hi i have a sri turbo mk4 z20 let! It was recently smoking really bad so i put it down to a common problem with a hairline crack in the turbo so i ordered and fitted a VXR turbo unit on sat the 10th!! Checked turbo once i got it off and as i predicted there is a crack in the turbo so i thought it was sure to cure the problem!! ran it over the weekend and done about 100 miles but its still smoking!! Can amyone help me or point me in the right direction or tell me any other common faults??? My next course of action is valve stem oil seals!!!!!