Carb spray is better for finding leaks than wd40.
if you have had to crush something in a bov I would say it's knackered , a friend had this on his evo and was causing him to loose boost hence making no power, we swapped it out and then was loads better. See if you can get hold of a standard recirc just for test purposes.
Turbo check, take the inter cooler off and then the pipe on the front of the turbo, gentles try moving the turbine towards you, if you can its fkcud, side to side there should be some play as when the engines on the oil takes up some slack.
Check the Y pipes under the inter cooler, these are made from paper it would seem and are prone to splitting . Failing that YouTube will help you diagnose your wastegate :)
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