This says it only works with Delphi products is this true? I am looking for a repeater, and I know the sirius one isn't as selective as this. I have an xpress2 I think sorry not sure of the model I know it was the cheepest one at the store. Anyway would this work with my radio, or am I just out of luck for a indoor Repeater? Also if it would work where can I buy it from? The two pages I saw it on said they were discontinued.