could be too rich mixture too! At least I have a boost gauge, and on a very rich mix on WOT, boost was there, but power starts to fade and the turbo sound too.
Run rich at WOT is a problem alot of times. How are you adding fuel? A few people have made posts on other threads talking about the car feeling stronger at part throttle then WOT.
I would also check the basic stuff like spark plugs and the tubing hose.
