So i have done the first but major part of installing my subwoofer and amp into my xj6, running the signal and remote wire from the head unit to the trunk. This is not an easy job and will require some patience! After doing some research and not finding any step by step guide i decided to write one after i did it myself. This applies to 95-97 XJ6 Base model only since the Vanden Plas has a subwoofer behind the back seat and this may be an issue(Youll see why later). This is the first part of the install, but the hardest!
Steps:
1. Remove all your junk out of your trunk. Remove the two plastic fasteners that hold up the carpet that covers your gas tank.
2. Remove the two fuse box covers that are in front of the bottom of the rear seat on both sides.
3.The bottom portion of the rear seat comes out first, on mine the seat simply pulled upwards towards the ceiling and out towards the front seats. yours may be fastened as mine should have been so look out for the fasteners which should be where the fuse box covers were that you removed.
4. The rear seat back where the headrests are can come out now. On the bottom there should be four black latches with one phillips screw and washer in each. These are now exposed since you took the bottom of the back seat out. once you remove all four, the seat can be removed now. Holding the bottom of the back, lift it upwards towards the ceiling and wiggle it a bit, there are no fasteners towards the top, it sorta hooks on.
5. remove the mat that lies over the frame of the car, it has plastice fasteners. This will expose wiring and what not.
6. The cover that is behind the head rests needs to be lifted up a bit. It has two black plastic fasteners in the front, remove them and towards the drivers side(USA MODEL) there is a space where a subwoofer would go if you had a vanden plas. This is where you will pass your signal and remote wires through to get to the trunk, it will have a sticky foam on it which can be lifted up enuff to run wire through, then run them down the back of the back seat and down to the center of the car in front of the rearseat vents\center console.
7. Now goto the front of the car and remove the arm rest, in order to do this you will need to remove the ski slope ashtray and the center armrest where the cupholder is. When looking down you will see there is carpet and towards the front of the carpet where the skislope is the carpet lifts up. This is where you will stick a sturdy hanger until it reaches the front of the backseat. this is not easy and takes patience. Dont force things as you can mess up a wire! Make sure you tape up the end of the hanger too so it slides through easier and reduces the chances of cutting a wire. Once its passed through, tire the wires up and pull the hanger back up and now you have you signal and remote wires ready for hook up.
8.Replace everything and move on to installing the amp and the subwoofer in the trunk.

 

I will post up a write up on how to wire the amp in the trunk. It is going to be alot easier than a car that has the battery in the front of the vehicle.

 

So what's with the rest of the install? I'm really curious about it, as I'm considering replacing whole sound system in my Jag And by the way, finished up, with detailed pictures, it would be a nice sticky