Good old Wiki:
[u]
http://en.wikipedia.org/wiki/Turbocharger gives a pretty good explanation of the theory and workings of a turbo system, with no mention of a screamer pipe
Looks like some sort of pressure relief valve MAY be needed (still not convinced) in the induction tract, but released gases are better fed back into the exhaust side in order to help keep turbo spinning so as to reduce lag. This means more plumbing and much less noise but what are you after, show or go?