Don Penny

I want to move my SPA Boost Pressure Sending Unit location from the turbo hose to the Intake Manifold.I am not familiar with the casting design of the Td5 Intake Manifold, but does anyone know what the actual function of what looks to be a "blow out plug" on the rear of the Td5 Intake Manifold? And secondly, does anyone know if it would be a bad or good idea to tap that area with a 1/8 BSP tap? Is the area thick enough to handle threading?Here is a pic of the area in question. I prefer to tap this area since it would eliminate the need to run the sending unit wires down the length of the manifold. Just a cleaner installation and shorter run for the wires. Thanks in advance. Cheers. Don