I took a mate for a ride who knows a bit about turbos, admittedly he's from the subaru side of the fence, but he said it definately doesnt sound like pinging. I use Shell V-Power all the time. After reading Mika's post I went for a drive and baby'd it for about 20mins, in traffic, suburban streets, and crusing at 100 on the highway. After that I gave it a kick in the guts, from 0 to about 150 and there was no sound at all, I did this 3 or 4 times with the same result. I'm thinking maybe the turbine is loose and makes a metal on metal noise when its cold, and it stops when the car warms up and the turbine is slick with oil. Sound possible? should the turbine move? the mate I took for a drive said he thought it shouldn't move and that maybe it had done a bearing, I have no idea though. thanks for your help guys