don't the S2.0 use the lighter and flimsier kinlin XR-200 rims?
How heavy are you? S4.0 has more material to stay rigid, but when you shave off weight from the rim, yet keep the spoke count low, you'll end up with flimsy.
Look into the S2.0 Max. They look pretty beefy(weight limit is 265 versus Soul's normal 210).