I have an 04 XJ8 with the stock stereo which confusingly Jaguar call Premium in the literature. The better stereo is called the Audiophile/Audiofile. The main difference I can see is that there is another amp, in the accessory stack in the trunck, which drives an extra set of woofers and all the other speakers. Since I have the stock amp, all the speakers are driven by the head unit. I have a spare audiofile amp and was hoping to just be able to plug it in, but no joy, there is no wiring in the trunk for the amp.
My question is, how difficult/impossible is this upgrade or should I forget about it?

Thanks

- Tim