I was asked to elaborate on the install of the LED headlights so .......
For background/memory jogger .... the lights are a 4x6 D.O.T. approved headlight. The XJ headlight bucket is 6x8, so some modifications had to be made. I removed the stock headlight and trim ring and laid the trim ring on an old plastic For Sale sign and traced that out. then I laid the new headlamp on and squared it up and traced that and cut it all out. I ended up with an "adapter/reducing ring". Then, using this template, I cut this out of some sheetmetal and ended up with this.

Because of inaccuracies with my tracing/cutting, a small amount of hand filing was necessary to make it fit just right. Here it is installed in the trim ring. I threw some hammered black on the adapter and the chrome ring

I had to file and fit the headlamp in to the trim ring also. Here it is installed.

When I (we, Tom helped!) went to install it, I discovered that not only is it smaller, it is also thinner. Even with the heat sink fins on the back. After messing with it a while and almost stopping for the night, we noticed some tabs at the back of the headlight bucket itself!
I asked for some channelocks and grabbed the tabs and bent them inward. Voila! problem solved! Here is a pic of the tabs we bent.

At that point it was a simple plug 'n play operation


So, there is the detailed install instruction for the XJ