Same mass flow means higher velocity in a smaller pipe. That higher velocity difference between the wall and fluid flow means more shear in the fluid, and more resistance to flow. Yes its best to remove all bottlenecks, but it's also been shown plenty that larger turbo inlets help even stock turbos.
-Dan
"Capitalization is the difference between helping your Uncle Jack off a horse, and helping your uncle jack off a horse." "'she' also likes to swap since I think I am going to need to give her to woody again." - Dvlhntr "full alphabetic boost mode" - ChristopherTheOne " Purrs like a sexually satisfied black panther." - BigTDogg "Two oil eating, angry, spinning triangles of death." - turtleboy on rotary engines