Nothing will probably work outside a couple year range. Oh, added cost? If you swap in a GM radio, dealer will have to program it with your VIN. Yes, radios are VIN specific and actually talk to your other modules...PCM/BCM/TCM etc etc. If the radio VIN doesn't match the PCM VIN, it won't work.
So...to make things easier. Your actually better off getting an aftermarket stereo, harness and chime module to make it work CORRECTLY. If you go in and start chopping this and that, you can actually cause more damage than one would think.
1997 Pontiac Bonneville SEi-SCRAPYARD
2000 Chevrolet Blazer LT 4X4 4.3L
2002 Chevrolet *-10 LS Ext Cab 4X4 5.7 V8