Well, if you try and put another GM radio in, like from a junk yard, even programming might not work, because on some systems, that replacement radio will have the VIN of the car it originally was in, and the other modules will not communicate with it...certain years, you could reprogram the new VIN in, but the newer models you couldn't.....this would drive New Car dealerships crazy, because they would always be trying to change radios in cars to sell them, by swapping them out of other cars on their lot....some radios come out easy, some don't, and there is a loss of time when the radios don't work and you have to swap them back......
You might be better off buying an aftermarket radio, with more options than the GM one, like MP3 capability, Bluetooth, even satellite radio, etc...
Places like Crutchfield are very helpful, in showing you how to wire up the new radio with your harness on the car, which may involve bypasssing the serial data line or not....
And they are a lot cheaper, than GM radios....