So, I am not a GM engineer, but this has me thinking. From what I understand about a GM engine computer, it is looking at things like air temp and pressure under the hood, listening for spark knock, reading the oxygen level in the exhaust via the 2 or more oxygen sensors, etc. All for 2 primary purposes: (1) to maintain a set air/fuel ratio and (2) to prevent spark knock in the engine.
If this assumption is basically correct, then it should still be possible to mount a supercharger and larger fuel injectors and see a significant hp/torque gain.
Why do I think this? Well, logically, if you add more air to the engine, the computer will adjust the fuel and ignition curves to maintain that desired air/fuel ratio and prevent spark knock. So, you should still see a 100 or more hp gain even without computer tuning.
Granted, being able to tune the computer would give you greater gains... But just bolting on a supercharger and installing larger injectors and possibly a larger throttle-body should still yield a gain.
Am I missing something here?