The 2200 kv 1515 1Y can handle 6s, but for those of us who are sticking with 4s, 2200kv might not be enough. I already tried an 8xl with a 20 tooth pinion gear, and that allowed for just enough top end for my liking, though it was a bit overgeared as motor and esc temps climbed very rapidly.
Check out my custom converted 8ight:
Sub 7lb, lowest CG of any 1/8 buggy