I can't seem to find any consensus…
Tal Rasha's bonus rains down meteors from the sky when you hit with an elemental attack. I've been trying to see if the meteors called down from Tal Rasha procs are affected by +Meteor damage affixes on gear as well as the +100% from the Nilfur's Boast boots (and the extra bonus for # of enemies hit).
Anyone know?
Best Answer
Builds (at least the ones I find on /r/Diablo3 and /r/Diablo3Wizards) are actually centered around just these.
As someone currently running that exact build (On PS4, so I cannot link bnet profile), I can tell you that both +Meteor damage and Nilfur boots absolutely do boost the effect. I got my Nilfur boots after completing my Tal Rasha's set, and saw a decent increase in damage. Additional information from the above reddit sub-forums as well as the Diablo 3 forums confirms this.
As far as I can tell, the proc from Tal Rasha's set behaves as if you had cast the meteor yourself with the appropriate element.