The science of light and in particular headlights in either sealed beam, halogen, HIR, HID, or LED, IMHO, is often not fully understood by the consumer. How many people actually take the time to understand lumens, temperature (color) of light and what the tradeoffs are between what the human eye most easily processes and what "looks" brighter?

But I digress.

The Lucas L2 for my XJS state they produce 13,000 Lumens for the pair. I couldn't find anything about their temperature (color/Kelvin), but I would surmise probably in the 6000 - 6500K range. They look much cooler/brighter than the 9004 halogen bulbs they replaced. I am still undecided if they produce more usable light that lets me see better and farther down the road. I do have to say the cooler temperature does look better, especially on my white XJS.

The bulbs came very nicely packaged. They are solidly made, and the bodies of the bulbs are fan cooled. I was very impressed with the build quality.

I found removing the front tires was the only way I could get to the bulb behind the access panel in the inner fender well. I removed the old bulbs and the Lucas L2s were ALMOST plug and play. I say almost as the stock Jaguar plastic locking ring had to be modified with a die grinder. The inner circle has to be enlarged to fit over the square body of the bulb.

The only other issue I had was after installing the passenger's side bulb the high beam wasn't working. I unplugged the bulb and discovered one of the male contact pins had bent while installing and wasn't indexing in its corresponding female hole. I was able to bend it back into place and all was well. Word of caution, make sure the pins are perfectly straight and gently and squarely plug in the bulbs to the vehicle's harness.

 

Those are cool looking bulbs.
fan cooled?

 

Yes. MSGGrunt says so in his post and you can see the actual fans in Picture #6

 

Looks brighter to me. On my specific xjs, they made a huge difference in lighting output.