One problem related to tire sidewall has been reported for the 2004 Jaguar XJ. The most recently reported issues are listed below.
Pirelli tires (asimmetrico 255/40 zr19 96y p zero) since may 18th, 2005, I have had 3 blowouts and 2 bubbles on the sidewall. 13,000 on car. 3 of the incidents were on tires that were used under a month (approx. 500miles. This car is unsafe to drive.