I've transplanted the S500 driver to the S600 quite a while ago and didn't have the time to update here with pics or impressions.
In summary, the S500 in S600 body were okay, roughly the same sound sig but much more closed in compared to stock.
Comfort wasn't better for me either as the S600 was barely "over-the-ears" for my ears.
A pair of Brainwavz pleather cushions
Fully disassembled SHP2000 with drivers and cables discarded.
S500 drivers, welcome to your new home.
Bare twisted Canare star quad cable here. Soldered to the driver and sound tested to be good.
Discard stock velour pads (they're horrible and uncomfortable...) and fit on the Brainwavz pads.
Kinda missed you, "upside down cat" ( I am cat lover extraordinaire myself ).
So - how does your latest creation sound like ?