buying new radio

I do not have much knowlege about satellite radios. I am buying a new sirius satellite. I currently have an very old Orbiter(sr4000) carkit. If i buy a new one will the carkit i currently have work for a newer model or do i have to buy a new one? thanks

I am pretty sure that most of the newer model plug and play receivers come with car kits. Maybe I am just assuming but both mine and my girlfirends both came with car kits and we have 2 different model receivers.