Well, seems that "surge" on the compressor side of the Turbo could only take place if there is exhaust surge on the Turbine side. So, the question would be what causes exhaust surge.
I see spiking of Turbo boost on acceleration occasionally, but I have never seen boost spiking on deceleration (letting off the throttle). The Compressor's out-put is directly related to the exhaust pressure and angle of the Vanes. Letting up on the accelerator pedal immediately results in the N75 releasing vacuum on the actuator thus changing the angle of the Vanes to reduce Turbine spin.
Obviously, unless that are some components malfunctioning, there shouldn't be any spiking.
Would be interesting to know what Darkside says causes "surge" or spiking.