[neallewis]

If its that competitive and there are vast speed differences between cars, and other racers are reluctant to talk about their setups, sounds to me like they are running non-blinky esc settings, timing/boost on the esc. As Mark has mentioned, 21.5 /2S is a downgrade in terms of meeting the fair and national spec of 13.5/1S/blinky, but if you are having to move to something else just to keep up, then something is amiss with the class rules at the club. If the club is relaxed about the spec rules, then swich your esc out of blinky and into full timing advance mode, and see how you compare then, before wasting your money on the 21.5 setup.