On the site it gives you the options of
Mountune only £449
Complete MT215 £799
Whats the difference?
http://www.mountunestore.com/Product/mTune-215-Power-Upgrade-Package/QMZCEVFWYP

Its explained in the text below the options what the Mtune is.
This is their handheld device for sending maps over. It also does 0-60 times and other stuff too

so Mtune only will just be for the handheld with the map
complete kit is with the hardware upgrades also

Ooooooh ok, easy when you look properly

Basically a flash drive for storing maps