ok so I don't know much about turbos physically, just how to deal with them in a thermodynamic system 
so what is going on with those 'circular' shaped holes cut around the inside ring
i hope that was a reasonable description of something i dont know what it is
Yep, it's an anti-surge housing. If you ever look at a compressor map, you will see the surge line on the left.
Surge Line: The map width is limited on the left by the surge line. This is basically "stalling" of the air flow at the compressor inlet. With too small a volume flow and too high a pressure ratio, the flow can no longer adhere to the suction side of the blades, with the result that the discharge process is interrupted. The air flow through the compressor is reversed until a stable pressure ratio with positive volume flow rate is reached, the pressure builds up again and the cycle repeats. This flow instability continues at a fixed frequency and the resultant noise is known as "surging".
There is also the case when the turbo starts providing more air than the engine can handle, the best example is when the throttle closes. Normally, the BOV will take care of this problem.
A ported housing allows air to bypass the outlet and enter the inlet. Big turbos on small engines can drift to the left of the surge line on a compressor map. In theory, a ported housing also allows quicker spoolup when/if this happens. It's also a nice fail-safe in case your BOV goes bad.
