Mr Damage, can I ask if it hasn't been mentioned already at what time did you hear it go? Wide open? Decel? Or neither? I'm assuming its at WOT but curious as to the answer. as it "may" point to a different suspect?
Always difficult dealing with OS engine issues. No flame to Keith C as he's always been great when I have spoken and dealt with him but distance makes issues hard and time consuming to sort. I've been down that road (Not with KC) and can't bring myself to travel again back down that road.
At least its not a "no warranty on race engine" scenario. Oh how many times I've heard that said to me.