While it's true that class 2 databus uses the factory radio to program factory keyless entry, reset service lights and low tire pressure lights, but only on certain cars. I only know of some Impalas and Monte Carlos use this setup. Trucks, and J bodies only have chimers, XM and onstar to worry about. I have not done any newer GM cars where the removal of factory stereo caused the service light to come on. PAC do make a converter box for the class 2 data bus to allow you to replace the factory radio with aftermarket radio while keeping the chime and Onstar with Bose without relocating the factory radio. One down side is if your vehicle has XM, you will loose that feature. If all else fails relocate the factory radio to the trunk. Forget about mounting the radio under the seat or the glovebox. It doesnt fit.