yep, i looked up the blue grove converion just now and its mod 1. that may present a problem. only mod 1 pinions i can find on ebay are 5mm shaft, larger than the vxl motors shaft. i do have a 9xl brushless motor which has a 5mm shaft, but its lower kv and may not be fast enough on 3s. and i dont have a esc that will handle 4s.