what does the DSP controller upgrade do for me?

[Badfrog]

I am sure this has been asked before and please point me to the correct thread (I did search!).
What will the Upgrade on a K40 do for me?
will it provide Z axis control?
will it give me the ability to vary the power for various "grey scale" via the software (i.e. when there are various degrees of gray scale in the file, will it burn deeper/darker?)
will it control end stops so if the work area selected in the software is larger than the physical work area it stops the xy travel and not try to force past the work space?
not sure what else to ask!