Hey mate, got a few pairs of s2 handles myself, i also replaced all my flexi handles like you are thinking of doing.
Most of the points have already been covered but this is what i have done,
1) ground the top clips off the handles with a grinding machine, smoothed them off so they are comfy.
2) removed the top plastic coating off the handles, as i did find after a while the hadles were a little wide for my fingers.
3) Replaced the plastic with my own neoprene sleeving design, if your interested in the sleeving give me a shout, ill sort u out
My thoughts, they beet any handle out there at the moment.
Hope this helps
Drew