10.5t or 13.5t brushless motor for indoor racing?

[muay30]

Im really getting into the indoor 1/10 touring car racing and just wondered which motor would best the best to get? Would a 10.5t be better or a 13.5t ? or is there not much difference? I have seen a good quality 13.5t for a reasonable price but i dont know enough about it to make a decision. Can anyone guide me i the right direction/ Many thanks in advance