I am getting a SI unit for x-mas and need to know what all I will need to hook it up to my 788. I want to use the GPS puck I have installed now for both units, share waypoints, and also get a regular ducer for the SI unit to use the downscan......what all will i need for this setup besides the obvious which are:

both units,
3 transducers (a skimmer, a TM mount, and the SI ducer),
power cables,
GPS antenna

thanks for filling me in on the rest!!!