Sensors sense shit, you know? The combination of sensors is complex, and the algorithyms that take the sensor data, interpret it, and make decisions for the engine, transmission and brakes at a rate of 50 times per second are complex. Whatever it is that they're doing, they were designed to work with the plenum. Removal of the plenum necessarily introduces unintended conditions that are outside of the algorithyms. Maybe the map can handle it under normal driving conditions, and maybe it'll throw codes. But when pushed to the limit of the performance envelope (like in an emergency maneuver), things may not work right just when you need them to work perfectly. My 2 cents.