He has a XJ6, not a XJR6, but I found the below which should help you, especially the first. By the way, if you have been offered $15K for your LS, I would sell it today. I only spent $15.6 plus $500 shipping for my 2004 Sport LS with 45K.
Thinking of buying XJR6 - The Jaguar XJ6 Forum...