Finally compustar has there new alarm out. Using spread spectrum technology, the range is 1.25 miles. You can check there web site for some local dealers. I'm not sure on a price yet, i gotta call up one of my friends at a local car audio place see if they've even got em yet.
I'm not sure if the other models are upgradable, but if they are i just may have to get one.
http://www.compustar.org