Looking for a sensor for car security system

I am working on a car security system based on GSM project, i still searching for the appropriate kind of sensor to use in the car which satisfy two conditions
1- Anti-Theft -----------> Door and glass sensors
2- Anti-Hijacking -------> certain kind of sensor ?

Also i want to make a remote safe shutdown of the car's engine when the car is hi-jacked.

Any help plz

there are seveeral ways to do things
you can put electronic switches on the door and window this is the simplest way.
or you can even put infrared tx and rx.
you can use shock tilt or capacitive sensor.
what is the output?
1) stop egnition
2) add a tracker
3) alarm?

you have first to decide how you r system will work, the sensors, output
so that to start the design

goodluck
let me know if you need help

I need to activate silent alarm by informing the user by sms then the user choose that to catch the car or lock doors , ....

I found that
for normal car thef (e.g : car stereo) -----> shock sensor
for car jacking or towing (whole car theft) ------> tilt sensor

Is this right ?

thanx for ur help

the tilt sensor will sense if the car was tilted. i.e. shaked with a certain degree.
The shock sensor will sense movement.

it seems you are confused. Let me know what are the scenarios you are thinking of

well..u can use RFID tags..

why to use RFID tags? What is the purpose?
yu want to help At least explain your point of view