I used my m40x headbridge to replace, much cheaper then the original. Also a bit lighter.
In the process I replace the left to right cable, just partially with 4n 99.99% silver single core cable. It was 0.2 ohm between L R. It went down to about 0.12.
Also solder the ear speaker cable nearer , but not to near to melt the coil output. Tiny cable, to the coil terminal instead of going thru the printed circuit traces.
Better sound overall