Lighting:
I replaced all of the interior lighting with Sylvania LED bulbs. There's 15 of them. I could have bought my girlfriend a nice piece of jewelry with what I paid in LED bulbs.
The side marker lights weren't working. When I removed them I found that the light sockets were rusty. Weird considering the car is rust free.
I couldn't find any new replacement Jaguar XJ8 parts to fix it.
Doing some research I found that Audi and VW used the same light socket Part# 1H0949111 and harness connector Part# D067B.
The front marker light housings were damaged from age and the heat of the bulbs.
I replaced one with a NOS one, and the other one I found on ebay.
I replaced the bulbs with LED bulbs so they won't succumb to anymore damage from the bulb heat.
I even cleaned up the light covers for the license plate light and replaced them with LED bulbs.