Hey man,
Still havent put my IEBC in because i was waiting for my Pivot stepping motor boost gauge to arrive. Its here and in now, I connected the tubing using a tee piece from the existing stock boost gauge take off hose.
My gtst has a cat back exhaust and a pod filter, and without the IEBC in is running 0.75 to 0.78 bar boost, which is 10.8 to 11.3 PSI. So no boost increase for me either, i'll just have to try for quicker boost build-up. Im pretty sure i dont even have a aftermarket dump/front pipe (unless its the rusty thing thats under the heat shielding.)
I know they are different cars and engines but i dont think the gauges would be off. I know mine is brand new.