with a gsm module http://www.telit.com/en/products/gsm...p_ac=show&p=11 running python script inside !!! you can do anything from sms .
the module have gpio lines and can be programmed to switch car locking system
a jumping code hard breaking algorithm can be made and put on both : telit module and n900.

warning !
additional cost may be applied. kilo free sms sim recommended.
outside gsm coverage regular key must be used.



i don' t need this because my car have rf perimeter key