At V12 Performance, we've come up with an excellent alternative to the expensive ($275-$300 each) and outmoded OEM catalytic converters. This aftermarket high-flow catalytic converter, manufactured by industry leader Magnaflow, will replace both the primary and secondary cat on the XJS V12 at less than 20% the cost. It is virtually the same size as the OEM secondary cat and mounts in the same place. OBDII compliant, EPA and CARB certified, its rated capacity is 3.4 liters so one on each side can easily handle the needs of the Jaguar 5.3 liter V12.
Since it is high-flow, it is significantly less restrictive than the OEM version and will also add horsepower to your XJS. This is a weld on item that any competent muffler shop can easily, quickly and inexpensively install.