Anyone know if there is an easy to install replacement for an old Narco MK 16? The NAV works OK, but the COMM side is kind of funky, and I know repairs on this old dinosaur are not going to happen. Because I use a portable GPS for nav, I wonder if a VOR receiver is really needed. Or is one expected to be in there if I ever would sell? I just can't see sticking money into a system I probably won't use.