I've been considering replacing the factory alpine stereo in my 2004 XJ8. There is no aftermarket support for the XJ8. But there are plenty of options for the S Type. The factory center console / radio controls appear the same.
Crutchfield has fit kits, wiring, steering control kits, etc for the S Type.

Does anyone know if the S Type wiring and stereo are the same as the XJ8?

 

Yes.

http://www.jimrothe.com/jaguar/acm-b...ackground.html

 

Thanks!

Does anyone know if the "standard" alpine stereo has an amplifier? My stock radio will have no sound at times and the next day it will work fine.

 

"Standard" in which model? Year? Trim level?

Edit: never mind. Just re-read your first post. Dunno the answer here, but somebody will chime in, I'm sure.