I believe that only two master keys can be active at the one time... So a theif will not be able to unlock the car with a seperate remote... Although, there's nothing stopping the theif hurling a brick or forcing enrty with a screwdriver...
If you want to install an alarm, look at the Toyota Alarm Upgrade options...
I work for Toyota so yeah, I know a bit here... Whereas I reckon toymods is Old Skool Celica based... When will they learn ...