I have a 2003 X-Type Jag with a Factory Sat/Nav System and I want to connect a USB Stick with music. Can I purchase some kind if accessory to connect to my Audio System?
Cheers :-)

 

Jag make a kit known as an ACM. It gives the car not only a USB input, but RCA jack inputs and an iPod input. Unfortunately Jag stopped making these kits some years back. They appear on EBay now and then, and there are still some in stock at the dealers.
They tend to be expensive. Around $400-$500 usd.
I bought a used one and haven't listened to anything except my iPod for years.
Good luck.