Disabling touchwiz and nova launcher questionsokay

Okay so i keep hearing alot of people talk about nova launcher, so im going to give it a try. Im one of those people that is about 95% satisfied with touchwiz so there alot to live up to.
Anyways, with nova do i disable touchwiz other than choice nova as my default? And does Nova drain ths battery any more than if i wasnt using it? Thanks.

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