Should I run my external wg vacum source from my brake booster or the compressor housing? 9-12 lb spring. thanks

 

compressor housing if you don't want to overspool your turbo. (max pressure gen will be wastegate spring)

brake booster if you want to make sure you get your 9-12lbs at the manifold..
(instead of having a pressure drop through the FMIC and seeing 8-12lbs at throttlebody)