"With a Dremel tool and a throttle body in close proximity, the inevitable happened; the Dremel tool suddenly attacked the throttle body! As the aluminum dust cleared, I wondered if the throttle body would ever return to service. I clutched the ignition key and didn't let go as I turned it over, expecting the scarred throttle body to propel its engine to disastrous speeds. The engine, however, quickly settled to a calm idle"
I intentionally left a rough surface, as the physics says so. To avoid issues with idle control, I made sure not to remove material too close to the butterfly valve. The air passage for the crankcase ventilation is a massive air block, I shaped it more aerodynamic using chemical metal.
After taking the picture, I decided to also bypass the coolant loop, so I cut off the coolant hose connectors. The coolant loop is to prevent the butterfly valve from freezing in cold weather, but even a WRX driven in -35 degC didn't have issues with a coolant loop bypass.
Stock throttle body for reference
Update: After 4 years, I've had no issues with the ported throttle body. Pickup on acceleration is sharper, which was the goal.