I just did this little mod, took about 15mintues, and I got about 30feet extra range from my keyfob.
In order to do this you will need:
-Soldering Iron
-Solder
-Flux (optional, but I needed it in order to get the solder to stick to the circuit board)
-Extra-fine sandpaper
-Razorblade
-Drill
-Very small drillbit
-Short piece of wire
-Electrical tape (optional)
Here's how to do it:
Take the keyfob apart, Remove the circuit board and scuff the antenna (the small rectangular box). Strip 1 end of the piece of wire you cut and solder it to the antenna, use flux if necessary. (Try not to get a huge blob of solder on there like I did, the solder I used was much too large in diameter).
Take a small drill bit (same size as wire diameter) and drill a hole through the circuit board in the spot that I show. BE EXTREMELY CAREFUL HERE!! CIRCUIT BOARDS ARE FRAGILE AND CAN CRACK!! ALSO, DO NOT HIT ANY TRACKS OR TRACES (hold the circuit board up a light, the green is where you can drill, where you can see copper or white paths you must not touch them!)
Insert wire through hole and wire down flat against the circuit board.
Flip it over and zig-zag the wire back and forth (you can do it a little nicer than I did, lol).
If you are using very soft wire you can probably skip this step, but my wire did not want to stay folded up, so I warped a piece of electrical tape around it.
Using the razorblade, cut the 2 top nubs off of the back 1/2 of the keyfob.
(they are still here in this pic)
Snap the keyfob back together and test it out!
I used to have to walk almost to the top of my driveway before the keyfob would work, now I can use the keyfob in the middle of my driveway (about 30 feet further).
Have fun!