Very brief impressions comparing the two:
- fuller sound across the FR / less airy spacious than stock
- more pronounced bass / slight less flat neutral than stock
Subjectively I find it sounds very pleasing and the slight change in the sound is definitely to my taste. I would probably have opted for the rwak if I don't have the stock unit already. However the difference is not big enough for me to send mine in for the mod.
(disclaimer: impressions with 1p2 and jh13fp on dsf tracks , the rwak240 was very new, the environment is quite noisy)
Not my cup of tea then,glad I didn't send it to get it modified.