Cant you just turn the boost down, ( I dont know anything about boost etc, only that our whiz kid fitter, who used to have a big American muscle car and took it to Santa Pod, boosted mine up a bit)
If your turbo is pushing out 25 psi is it possible to cut it back a bit. Cant remember what he pushed mine up to, think it was 2 psi above whatever. Anymore and he said it caused the engine to knock.
Best of luck and hope its sorted.
