Gasket leak could explain the noise, also the detonation I was getting on the track... If it's leaking out boost, the turbo will be running harder to maintain the set pressure (16psi) and thus getting hotter and hotter... Right? Would it also throw off the mixtures since the AFM is reading different to what is actually entering the engine? (though, in this case it'd be richer???) and it didn't seem to be running rich at all. Will plug up my new Wideband on the weekend