The neterlands is similar to the Uk in that the requirements for vehicle security are more stringent than other countries in the world. As your car is US spec it will not have the wiring for the additional security required in the netherlands by the local insurers. The parts that are missing are the battery backed siren and tilt sensor. I have a kit available for installing these items allowing your car to meet the local demands (contact me if you are interested). Fitting an aftermarket alarm isnt so easy on a 997 as the porsche alarm cannot be deactivated so it conflicts with the aftermarket one. Better to retro fit the OEM parts and loom. This is what I did with my 987s which uses the same control modules and front end wiring as the 997.I even have a letter from a local porsche agent confirming the car now meets the Uk/ Netherlands alarm spec as new from the factory.