The article said the code has to be written for each car so I would assume that any change in audio gear would require a recoding. Don't know for sure. There is definitely a downside to it but I've known audio junkies that would go to all kinds of trouble for "the sound".
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GXP
Ordered 06/24/06, built 01/04/07, delivered 01/20/07.
DEEP, AC, ebony cloth, Monsoon, XM, headliner, power seat adjuster...
Mods: J-type Shorty antenna, Red Pontiac decal on wheel hubs...