I'm kinda stuck on the where to tap into for my speedo and tach on the defi vsd basis heads up. Should i tap off the wires going into the gauge cluster? and if so which ones and proper settings OR off the ecu wiring? and if so which ones?

FOr a 2004 wrx. Thanks, and at ravensblade, i just saw the ecu pin for engine speed which im assuming is for the tach however where is the speedo, its not on the diagram so i'm thinking of tapping off the wires going to my cluster, maybe that'll be ok?????