I would look into getting the Alpine 8063. It has a dual radar zone, and can be hooked up with a pager. It will give a warning if the car is bumped lightly or if you stand by the car for more than a few seconds. These settings can be configured for times you don't want it so sensitive, like when your in a parking lot. The pager doesn't have the greatest range (about 50 feet) but it's meant more as an interactive pager than anything else. As well there is the option of adding the display module which can record the last five events. I use it myself and haven't had any problems with it. I've heard pretty good things about Clifford too. Hope this helps.