I run the Hallman mounted in the engine bay and it has been a very reliable piece. With the EWG, it holds 26 psi all the way to redline without a hick-up. It has been working as intended for a long time in my ride.
In my mind, it is the most reliable way to control boost. It is very sensative and give you lots of control.
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GT35R STi
Topspeed Tuned