Theres a lot of work that is involved.. well not a lot but here is what we did.
First, remove the 07 trunk lid, remove everything from in there. cut the wires near the hinge for the lid.
Removed the tail lights...
(would have removed the bumper but the new one is not here yet)
The striker should be removed and replaced with an older style striker for the trunk lid more on this...
ok As for rewiring... it was NOT hard at all. We bolted the older style lid onto the car and just tested which wires went where. They pretty much matched up, but the older style lid also used heavier gauge wire too for the latch and the third brake light and license plate lights. There is also the wires that tell the car whether or not the trunk id open... the lid I got did not have those, so we simple soldered them together so trick the car into thinking it was closed although I guess if you wanted to you could jury rig something up so keep that functionality but really... who doesn't know if their trunk is open, and not only that if you are driving is stays closed anyway lol.
Tail lights was easy. However you most likely will not be able to use the stock brake/turn signal light bulb socket as its bigger. I had a wiring harness for the rear of an 03 handy so we wired in those sockets... the blue/green wire is also your turn/brake light. There is a just brake light in the harness on the driver side in the trunk if you want to wire that too.
Now for the striker... I didn't have one handy... so we kinda cut part of the protecting mental around the latch on the new lid off. It works for now but I gotta slam the thing shut until I get a new striker
The bumper from an 04 to an 05-07 is different so you will need a new one I am just waiting on mine.
I would also recommend buffing the hell out of your new lid... since its older than the car.
As far as fitment for a spoiler from my 07 to this 03 lid... It fits ok... But I am going to fit in the gaps with silicone since the new lid is slightly more curved and the lid that came with the car was flat.
Your lock tumbler from your 05-07 lid will not work in the older style lid unless you can find yourself a nice 04 trunk lid... But you can have a tumbler redone to work with your stock key.
Any other questions at all?
"Whoopie! That may have been a small one for Neil but it was a long one for me!" - Pete Conrad stepping off the LEM onto the lunar surface during Apollo 12.