Not quite, Patrick; all the smarts for the tuner (including interpolation of signal strength compensation values, snap tuning to RDS AF frequencies for monitoring, etc) are all done *in the player code*. The tuner protocol doesn't have "tune to xxx" commands, it has "3 byte tuner I2C send" and "8 byte I2C send" for example. If the alternate modules don't use the same philips tuner chip (6840 or something newer in the same range, I think) then it'd require significant hacking to get it working.

The player software also reads the I2C eeprom in the tuner module for calibration values.

Without major player software mods, you're really going to have to go for the 1385 weatherband module, which at least is backwards compatible with the current software (though weatherband support would require some more work on the player)

Hugo