RACE the Tekin's, they are fine! They are a reputable company and will get you plenty of run time and great power without fading or going soft. I race 2 B4's, one with a 10.5t and the other with a 13.5t (Tekin RS Pro ESC's w/Orion Motors). I have all sorts of Lipo's by SMC, Reedy, Tekin & Orion. They all work great, your overall setup is most important! Run what you got, setup your ESC/motor timing/gearing/fdr correctly & balance charge/discharge the Lipo's correctly and have fun...