Reply to Some s4 guidance please??

Using traktor 2.1.1 I'm having a few issues that are probably staring me in the face some info regarding the following points be much appreciated..

When using your setting in traktor and you modify them is that what's known as your tsi?
Can they be saved and and exported to another mac and work in the same?
Can someone explain on how to do this?

When downloading other mappings like the djtt one does this overwrite the one I'm currently using and if so how would I get it back?

When I push the master button on the unit it kills all the volume???
Which I thought would be for master sync?

Im not very clued up on mapping and a little reluctant of changing settings in the software which could funk it, this was one of the sections in the traktor bible that totally confused me.

Thanks