Some of the P3 gauges for various cars have them integrated and read from the OB port as long as you select the option. Mine does not have the “boost tap”.
From their website:
“Specifically designed to support the Audi B7 A4 / S4 / RS4 platforms. Reads boost and all data directly from the diagnostics port for fast plug and play install.”
EDIT: changing the title of this thread.