I'm thinking about upgrading to a BM53/4.

I have searched a bunch of threads and the only differences that I have been able to find are: (correct me if I'm wrong)

BM53:
Sirius = yes
TMC = no
MP3 = yes (sept 05->)
world radio = yes (i.e. USA/ECE/Ocean)

BM54:
Sirius = ?
TMC = yes
MP3 = yes (sept 05->)
world radio = ?

I'm aware that USA=sirius on with the BM53, is this the case of the 54 if it has a USA mode?

Also, the antenna diversity module has to be replaced if updating from a old "round connector" radio.

Please chime in with info.