I could be mistaken, but wasn't the LX-5 expecting nominal 16 ohm drivers?
(like LE15A, or was there more than one LX-5 version?)
Horn loading the 2205 might raise the driver's impedance some... which
would tend to lower the crossover for the bass driver (only)... perhaps
making a hole where the K-horn is already running out of steam (400-500Hz)
... that's about all I can think of without available measurements with
respect to frequency (impedance and/or amplitude).
Bottom line... if you like what you're hearing, why poke at it?
(OK... I would too
)
Edit: why 4ohm drivers in horn loaded enclosures?
Some interesting reading:
http://www.volvotreter.de/khorn.htm
-grumpy