That is just 'Wakeboard Cruise'. You can not set it to hold at a specific speed - you get the boat to speed and then push the 'cruise' button.
Notice the control module says 'for upgrade info call...'
You can upgrade the module to the pro version, but you would need to buy a paddle wheel, a new display unit and servo. Might as well get it new for $1100 and install it right.
I have a SN2001 and it works like a charm... get the ACME 542 prop - that makes a world of difference.