scytek blows, don't get anything unless is is made by DEI or AUDIOVOX. everything else becomes a headache in the long run trust me. personally i prefer viper, python,Clifford these are made by DEI, you spend a bit more money but its worth it, and tell whoever installs it to turn the sensitivity of the shock sensors down. most installers turn them all the way up assuming that the customer wants the maximum protection, but with every vibration the alarm goes off and it gets annoying. also invest in a microphone sensor, it was mainly designed so that is someone tossed a spark plug through your window it would trigger. it works well.