I just did the quick-n-easy version of this mod...just pulled the antenna wire out of the bundle...no extra length wire added. Before, I had to have the remote right on the driver's window to activate it. Now, it will work from at least 35' away. That was more than enough for me, so I didn't bother finding the limit.
Interestingly, I didn't have a foam block in mine that gave a few people some problems. Maybe that is the mysterious "sound deadening" in the Touring Package?
I also did not have the razor sharp exposed edges. There was very thin (~1/8") adhesive-backed foam sheet material covering the area and wrapped over the edges of all the aluminum.
Joking aside, my guess is that the earlier cars just had the controller tossed in there on the thin foam sheeting and, due to the controller rattling around in there, they made a running change to stuff the foam block in in place of the foam sheeting.
This was a very quick and easy mod that should have been done at the factory. Anybody with a #2 Philips screwdriver can do it in a few minutes.