Hi. I'm new here. I have a question about GPS antennas. For use with the OEM PCM2 unit, is the only GPS antenna that would work (and can be installed in the OEM location) the OEM Porsche GPS antenna? Can an aftermarket antenna work just as well and, if so, can they be installed the same place OEM antennas are installed? If aftermarket (cheaper) antennas work OK, are there any recommendations as to which one is best? Any input would be greatly appreciated! Thanks in advance!