Well fire Main has no need for Sasuke, you would do better with Anko (you get combo form him, but dmg boost from anko, which is far better).
However... you c*ways use them in ranked and in survival, so yeah... if you like your team upgrade them farther, if you don't... then leave them alone, otherwise you're just wasting stamina and exchange points. This post was last edited by 101***@facebook at 2016-8-31 04:08

i suggest continue upgrading kabuto :) as he is very useful in rank team and in survival :)

i don't use kabuto or sasuke now because i use different ninjas hehe :)

as for sasuke its ok :) you can still use in rank team or survival just like kabuto :) im currently upgrading both :)