replacement immobilizer
 

hey can anyone tell me if the immobilizer and ecu are interchangable between 2000 and 2001 986's, both non turbo? thanks

The ECU in the 2001 and 2000 models are both version 7.2 and are compatible. The immobilizer modules can be replaced with another one with the same part number.
BUT the transponder in the key, the immobilizer, and the ECU all have to be coded to work together as a set. You can not just take one part such as the ECU from one car and swap it into another without also swapping the immobilizer and key transponder too - or having the set reprogrammed to work. The reprogramming is generally not a DIY, but can be done a lot cheaper than at the dealership.
There's plenty more detail to be found if you search the forum.

You do realize that all Boxsters up until the 718 models are non turbo, unless someone modified the engine.