By changing the file format, you automatically break searching done by any non-compression-savvy program. Since it's a breaking change, you get to define whatever search path logic makes sense. Thus this:
example.mpd ➔ search for "example.ldrz"
is just as valid as this:
example.mpd ➔ search for "example.mpdz"
example.mpd ➔ search for "example.ldrz"
is just as valid as this:
example.mpd ➔ search for "example.mpdz"