turbine clipping or open the bore?
 

i'm re-assembling the engine and since the turbo (hybrid S4) is off the car, i was thinking if by increasing the bore diameter (see attachment) it would be an alternative to clipping the wheel to reduce backpressure?

i was thinking increasing the diameter by 1/8" (blue dashed line).

actually, seems to me this approach is better for reducing backpressure and increasing flow.

any thoughts or experience out there?