You need to get the following parts as a set from the same car. Years 97-00.
1. Key head.
2. Emobelizee reader on ignition key.
3. Alarm/ impbilizer module under driver seat.
4. ECU in trunk.
You can fine complete sets on eBay, or just contact Woody on the forum.
http://986forum.com/forums/boxster-parts-sale-wanted/52469-parting-out-whole-lot-boxsters.html