with how much haste? That is to be considered since there is a point where you will cast way more PW:S. In terms of quick math: 540 additional haste requires >400 Spirit to compensate [1], with a non t17 sequence. Results must be re-computed with a updated sequence (the one of which you are talking)
That is also the point, why I wanted to add to this thread that you have to be careful with mark of rapid replication (Auto-Repairing Autoclave respectively) since it does have a lot of spirit. But the additional spirit it provides compared to other spirit trinkets does NOT compensate compensate the mana you are losing through using haste as a secondary stat (proc/use) instead of another secondary stat trinket.
[1] Compare:
http://www.mmo-champion.com/threads/...1#post31833168