Hi, MrMPX!
Sorry, I didn't know you were posting form the USA. And I want to point out that I am not an MPX-man, just a customer as your are. The MPX-forum is not the MPX-service, it is supporters and custormers who write about MPX-products here.
It certainly is possible to send the TX to Germany and they will send it back to the USA - it is only a question who pays what shipping. And I don't know what FCC is good or, at least in combination with an upgrade.
Try to contact MULTIPLEX directly. You find the addresses and phonenumbers on the MULTPLEX-homepage.
best regards
profimc