First off, thanks go to Scott451 at the Tesla Motors Club for the idea.

First 'ible so bear with me.

Step 1: Supplies

The tools that will be used in this project:
Soldering Iron
Wire Cutters/Strippers
Heat gun/micro torch
Screw Drivers - a torex multi bit tool, phillips #2
Multimeter

Items needed:
2 LED light strips - Autozone
Solder - Radioshack
Heat shrink tubing - Radioshack
wire - Radioshack
3M Automotive Moulding Mount Tape (double sided foam tape) - Autozone
Patience

Step 2: Disassembly

Take apart the trunk light by removing the two screws holding it in place. This not only removes the lens from the holder, but also frees the holder from the trunk exposing the two supply wires that we will solder onto.

We will also need to remove some of the trunk screws along the right side of the trunk along the rear of the roadster. DO NOT DROP ANY OF THE SCREWS as it is a pain to retrieve them.

Step 3: Wire Routage

Route the wires along the rear of the trunk behind the right side tail lights and between the trunk and the rear of the car until you get to the trunk light. Run the wires along the air shock of the trunk lid and secure the wires to the trunk lid with the 3M tape.

Step 4: Mount the LED Strips

Decide where the LEDs will reside.

Mount the LED strips to the trunk lid using the 3M tape.

Step 5: Electrical Connections

Remove the plastic shroud covering the electrical connections to the light. Solder one wire to each of the terminals. Replace the shroud.

Step 6: Plus or Minus

Since you ran the wires without marking them you need to find out which is the positive and which is the negative. Take out your multimeter and test for voltage across the wires. If the voltage is in the positive voltage range you have found the correct polarity, make a note which wire is which.

Step 7: Reassembly

Reconnect the trunk light to the wires and reinstall it back into the original position and install all of the screws you removed from the trunk area.

Step 8: Electrical Connections Cont.

Remember to put the heat shrink tube on the wires before soldering them. Connect the Red wire from the LED strips to the Positive (Red Multimeter lead)wire that you found in step 6. Connect the Black wire from the LED strips to the Negative (Black Multimeter lead) wire you found in step 6. If the lights turn on you have wired it correctly. If they didn't, reverse the connections. Solder the connections. Use heat shrink tubing once the connections have cooled to insulate them, as the name implies heat to shrink the tubing. Stick the wires up to the trunk lid with the 3M tape.