Audio Systems: Delco AM/FM cd cssette RDS install, aple ipod, chevy express

Question
I have a 2004 Chevy express 2500 van with a factory AM/FM
radio in it.  I just bought form a salvage yard a Delco AM/FM cd
cssette RDS (from a 2003 chevy express van) which I wish to
have installed by a company in Athens, GA called Custom
Sounds.  They want $50.00 -definitely reasonable.

The Chevy dealer wants $40.00 to reprogram?  Must they sync
the VIN with the radio or is this the old system of entering four
digits?  Why can't one just install a readio and be done with it.  
NOBODY wahts to steal a factory radio.  They are expensive but
geerally lousy radios.  I have awork van and cd and cassette
would be nice, but the price iskilling me for a used radio install.

Any thughts?

thanks in advance,

Larry

Answer
no way out dealer needs to input vin number on radio
this radio is fancy and does a lot of thing  there is xm input onstart input aux dvd controls it can also control any aple ipod

also when this new radio is in your vehicle it will control the chime noise  the rpm gauge the low fuel light and air bag information  is not just a radio unplug yours and you will see al the things that will stop working in your vehicle
sorry i can not help more