a spliting tool?
 

I was wondering if there was a way to perfectly split a mesh in half...i want to use nex to make a game model based on my high res zbrush model and the number of polys are making it impossible for me to split it by selecting.

Use the cut faces tool with the axis set to YZ, or whatever plane your model is symmetrical across. Then select all the faces on one side and hit delete.

Hopefully that was your question.