Even I wanted to do something like this and that's why started the thread "http://www.theautomotiveindia.com/forums/accessories-spare-parts/4970-two-way-car-security-systems.html" please go through it as well and comment.
Seems there are very less people here who want such an install (am still waiting for Guru's inputs). I had a suggestion we can get this as bulk order if more people join in so that we can have a good discount as well. Do let me know if you are interested.
@Mods: Please merge threads if required.