Boost spike solved
 

Installed a dawes device a few months ago to control my boost on a 1993 WRX, I have had a problem with boost spiking so last weekend I drilled the existing hole out to 1.5mm. Took it for a run and it no longer spikes. It does boost very slightly more with this hole so its advisable to screw it back a little before testing after you have drilled the hole. This is just for reference for people searching as I could not find a definative yes or no on here as to whether or not this would solve my problem.

that should do the trick. It's what the hole is there for, so making it larger was the right think to do. Just back it off a bit to get the boost back where you want it.

What exactly does the hole do? I know theres some sort of ball under a spring so that as the turbo pressure builds up the spring gets compressed letting pressurised air through to the actuator, does the hole just act as a bleed valve untill the actuator does its thing(ie delay between spring being pushed and actuator starting)?