Pulled off the intake tube between the MAS and the turbo, and trimmed down the dump tube to a more reasonable length (I can't believe how far they jammed that thing down the intake; that can't possibly be good for airflow). In the process of gluing the dump tube back in with KB Weld, will re-install in the morning and test.
Later: Reinstalled, and all is well. No noticable change in either performance or sound. I don't think this mod is really worth the trouble, although it doesn't seem to harm anything.