The dual stage microwave sensors are no longer available thru Autowatch, however we do use a Dynamco one with no problems.
The 288 RLI has now been discontinued, as remote start is illegal in Australia and the company doesnt wanna carry the burden of incorrectly installed Autowatch remote start alarms.
An ultrasonics sensor doesnt get hidden away, the control module does yes, but the two little eyelets which emit the ultrasonic beam have to go somewhere around the A pillar area facing towards the rear of the vehicle.
Also I have been fitting Autowatch for years now, and have never had an issue with the antenna on the module, nor have i had a problem with a remote. Thats not to say that it wont happen because no product is faultless, but it hasnt happened up to now.
All sirens have to be 120db rated any louder and it is not legal to have in your car. The only siren you can use with the 456 is the keyless digital battery back up siren.
The 160RLI has a slightly bigger siren but the volume is pretty much similar.