Yeah, they just short through the plastic cracks. Where is the exhaust blowing? When I bought mine the exhaust was fine and quiet. 1000 miles later I cracked it right in the middle on a factory weld so removed it all and had to spend half a day welding it all up together as I found more tiny holes through different pipe joins and bends in the middle section. Then a month or two later the rear left box failed so had to replace that too
Its fine now, hope it last for few more years.
1997, 4.0 LWB X300 - Unlucky car but still a daily driver.
1988, 3.6S XJS - Never ending restoration project.
1994, 3.2S X300 - Accident damaged, October 2015. Gone!
1994, 3.2S XJ40 - Long gone.