I was after a ported shroud on my new turbo, I ended up gettin a brand new garret turbo from someone who never used it but it had no anti surge ported shroud and when I spoke the CRTurbo's they said its better without as it will be slightly more responsive than if it was ported
thats what i was thinking, if theres a small open port leading back into the filter side it must impact response after a gear change, i need to find out how much now i could gain and if it will work ok and possibly get a non ported shroud if there available for a gt4094r.