I never ran the SXX, but I can tell you the Flow is a HUGE improvement over the Tekin RS! After I bought one to replace my RS in blinky 17.5, my lap times were nearly 1 second faster per lap (same track/setup every weekend). I went from barely making the top 10, to being a serious contender in blinky.

Shortly after, I picked up another Flow to replace the RS in my VTA/Scale Spec car, and once again saw improvements (nearly .5 seconds per lap).