What you need is the the retrofit version of the spa pack which comes additionally with the topside control panel as well as cables in case you need different on your pump etc., that you currently have.  Yes the VS501Z will handle your situation perfectly.  You remove the spa pack by loosing the end unions, removing the cables from it, reattaching the unions to the new spa pack and reattaching the cables as well as the new top side control panel.  A detailed installation manual is not supplied by Balboa and for that reason we have produced our own.  That and technical support is what differentiates us from other suppliers, who just sell the box and you are on your own.  We do not however supply the manual without an order. Warranty on the spa pack is 2 years and on the top side panel 1 year.  Ki is on sale for $465 + $25 shipping by UPS ground.

Dieter Jung

Tech Support

Northern Lights Group