Just wanted to share a project I just finished today. I had a working original key (with the keyless/trunk pop) but I only had the one. After seeing the price of a replacement I decided to find another way to get a replacement key.
https://www.youtube.com/watch?v=98-dVghDcog
Quick background, I work in the car audio industry so keyless entry/alarms/remote start is something I deal with on a regular basis.
So I had one of the installers help me figure out a plan. We had a
Viper 5806v that was parted out but still had the brain/remote/antenna so I picked that up for $95 and had it installed for $100. It arms and disarms the factory alarm and will eventually pop the front/rear trunk too. He had problems with the triggers for the two trunks but we should have that solved within a couple days.
The remote is a 2 way system so the remote is paged to confirm the car locks/unlocks, or if the shock sensor is triggered.
As far as the key goes, I swapped the transponder pill and key shaft from my original key to
this 911 fob.
Now I have a keyless entry system and factory 911 key and can preserve my original boxster key. No more worrying about that $400+ replacement cost..
This could be done with any keyless entry system so long as it has atleast 2 auxiliary triggers for the front and rear trunks.